1
|
Thum C, Roy NC, Everett DW, McNabb WC. Variation in milk fat globule size and composition: A source of bioactives for human health. Crit Rev Food Sci Nutr 2021; 63:87-113. [PMID: 34190660 DOI: 10.1080/10408398.2021.1944049] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Milk fat globules (MFGs) are secreted from the mammalian gland and are composed of a triacylglycerol core surrounded by a triple membrane structure, the milk fat globule membrane (MFGM). The MFGM contains complex lipids and proteins reported to have nutritional, immunological, neurological and digestive functions. Human and ruminant milk are shown to share a similar MFG structure but with different size, profile and abundance of protein and polar lipids. This review summarizes the reported data on human, bovine, caprine and ovine MFG composition and concentration of bioactive components in different MFG-size fractions. A comprehensive understanding of compositional variations between milk from different species and MFG size fractions may help promote various milk sources as targeted supplements to improve human development and health. MFG size and MFGM composition are species-specific and affected by lactation, diet and breed (or maternal origin). Purification and enrichment methods for some bioactive proteins and lipids present in the MFGM have yet to be established or are not scaled sufficiently to be used to supplement human diets. To overcome this problem, MFG size selection through fractionation or herd selection may provide a convenient way to pre-enrich the MFG fraction with specific protein and lipid components to fulfill human dietary and health requirements.
Collapse
Affiliation(s)
- Caroline Thum
- AgResearch, Grasslands Research Centre, Palmerston North, New Zealand.,Riddet Institute, Palmerston North, New Zealand
| | - Nicole C Roy
- AgResearch, Grasslands Research Centre, Palmerston North, New Zealand.,Riddet Institute, Palmerston North, New Zealand.,High-Value Nutrition National Science Challenge, The University of Auckland, Auckland, New Zealand.,Department of Human Nutrition, University of Otago, Dunedin, New Zealand
| | - David W Everett
- AgResearch, Grasslands Research Centre, Palmerston North, New Zealand.,Riddet Institute, Palmerston North, New Zealand
| | - Warren C McNabb
- Riddet Institute, Palmerston North, New Zealand.,High-Value Nutrition National Science Challenge, The University of Auckland, Auckland, New Zealand
| |
Collapse
|
2
|
The Functional Power of the Human Milk Proteome. Nutrients 2019; 11:nu11081834. [PMID: 31398857 PMCID: PMC6723708 DOI: 10.3390/nu11081834] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 08/02/2019] [Accepted: 08/06/2019] [Indexed: 12/14/2022] Open
Abstract
Human milk is the most complete and ideal form of nutrition for the developing infant. The composition of human milk consistently changes throughout lactation to meet the changing functional needs of the infant. The human milk proteome is an essential milk component consisting of proteins, including enzymes/proteases, glycoproteins, and endogenous peptides. These compounds may contribute to the healthy development in a synergistic way by affecting growth, maturation of the immune system, from innate to adaptive immunity, and the gut. A comprehensive overview of the human milk proteome, covering all of its components, is lacking, even though numerous analyses of human milk proteins have been reported. Such data could substantially aid in our understanding of the functionality of each constituent of the proteome. This review will highlight each of the aforementioned components of human milk and emphasize the functionality of the proteome throughout lactation, including nutrient delivery and enhanced bioavailability of nutrients for growth, cognitive development, immune defense, and gut maturation.
Collapse
|
3
|
Label-free quantitative proteomic analysis of milk fat globule membrane proteins of yak and cow and identification of proteins associated with glucose and lipid metabolism. Food Chem 2019; 275:59-68. [DOI: 10.1016/j.foodchem.2018.09.044] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 09/05/2018] [Accepted: 09/07/2018] [Indexed: 11/19/2022]
|
4
|
Johansson BB, Fjeld K, El Jellas K, Gravdal A, Dalva M, Tjora E, Ræder H, Kulkarni RN, Johansson S, Njølstad PR, Molven A. The role of the carboxyl ester lipase (CEL) gene in pancreatic disease. Pancreatology 2018; 18:12-19. [PMID: 29233499 DOI: 10.1016/j.pan.2017.12.001] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Revised: 11/28/2017] [Accepted: 12/01/2017] [Indexed: 12/11/2022]
Abstract
The enzyme carboxyl ester lipase (CEL), also known as bile salt-dependent or -stimulated lipase (BSDL, BSSL), hydrolyzes dietary fat, cholesteryl esters and fat-soluble vitamins in the duodenum. CEL is mainly expressed in pancreatic acinar cells and lactating mammary glands. The human CEL gene resides on chromosome 9q34.3 and contains a variable number of tandem repeats (VNTR) region that encodes a mucin-like protein tail. Although the number of normal repeats does not appear to significantly influence the risk for pancreatic disease, single-base pair deletions in the first VNTR repeat cause a syndrome of endocrine and exocrine dysfunction denoted MODY8. Hallmarks are low fecal elastase levels and pancreatic lipomatosis manifesting before the age of twenty, followed by development of diabetes and pancreatic cysts later in life. The mutant protein forms intracellular and extracellular aggregates, suggesting that MODY8 is a protein misfolding disease. Recently, a recombined allele between CEL and its pseudogene CELP was discovered. This allele (CEL-HYB) encodes a chimeric protein with impaired secretion increasing five-fold the risk for chronic pancreatitis. The CEL gene has proven to be exceptionally polymorphic due to copy number variants of the CEL-CELP locus and alterations involving the VNTR. Genome-wide association studies or deep sequencing cannot easily pick up this wealth of genetic variation. CEL is therefore an attractive candidate gene for further exploration of links to pancreatic disease.
Collapse
Affiliation(s)
- Bente B Johansson
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway; Department of Pediatrics and Adolescent Medicine, Haukeland University Hospital, Bergen, Norway
| | - Karianne Fjeld
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway; Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway
| | - Khadija El Jellas
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway; Gade Laboratory for Pathology, Department of Clinical Medicine, University of Bergen, Bergen, Norway; Department of Pathology, Haukeland University Hospital, Bergen, Norway
| | - Anny Gravdal
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway; Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway; Gade Laboratory for Pathology, Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Monica Dalva
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway; Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway; Gade Laboratory for Pathology, Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Erling Tjora
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway; Department of Pediatrics and Adolescent Medicine, Haukeland University Hospital, Bergen, Norway
| | - Helge Ræder
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway; Department of Pediatrics and Adolescent Medicine, Haukeland University Hospital, Bergen, Norway
| | - Rohit N Kulkarni
- Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA; Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Stefan Johansson
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway; Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway
| | - Pål R Njølstad
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway; Department of Pediatrics and Adolescent Medicine, Haukeland University Hospital, Bergen, Norway
| | - Anders Molven
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway; Gade Laboratory for Pathology, Department of Clinical Medicine, University of Bergen, Bergen, Norway; Department of Pathology, Haukeland University Hospital, Bergen, Norway.
| |
Collapse
|
5
|
Wang Y, Ding F, Wang T, Liu W, Lindquist S, Hernell O, Wang J, Li J, Li L, Zhao Y, Dai Y, Li N. Purification and characterization of recombinant human bile salt-stimulated lipase expressed in milk of transgenic cloned cows. PLoS One 2017; 12:e0176864. [PMID: 28475629 PMCID: PMC5419509 DOI: 10.1371/journal.pone.0176864] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 04/18/2017] [Indexed: 01/13/2023] Open
Abstract
Bile salt-stimulated lipase (BSSL) is a lipolytic digestive enzyme with broad substrate specificity secreted from exocrine pancreas into the intestinal lumen in all species and from the lactating mammary gland into the milk of some species, notably humans but not cows. BSSL in breast milk facilitates digestion and absorption of milk fat and promotes growth of small for gestational age preterm infants. Thus, purified recombinant human BSSL (rhBSSL) can be used for treatment of patients with fat malabsorption and expressing rhBSSL in the milk of transgenic cloned cows would therefore be a mean to meet a medical need. In the present study, a vector pBAC-hLF-hBSSL was constructed, which efficiently expressed active rhBSSL in milk of transgenic cloned cows to a concentration of 9.8 mg/ml. The rhBSSL purified from cow milk had the same enzymatic activity, N-terminal amino acid sequence, amino acid composition and isoelectric point and similar physicochemical characteristics as human native BSSL. Our study supports the use of transgenic cattle for the cost-competitive, large-scale production of therapeutic rhBSSL.
Collapse
Affiliation(s)
- Yuhang Wang
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Fangrong Ding
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Tao Wang
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Wenjie Liu
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Susanne Lindquist
- Department of Clinical Sciences, Pediatrics, Umeå University, Umeå, Sweden
| | - Olle Hernell
- Department of Clinical Sciences, Pediatrics, Umeå University, Umeå, Sweden
| | - Jianwu Wang
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Jing Li
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Ling Li
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Yaofeng Zhao
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Yunping Dai
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
- * E-mail: (YD); (NL)
| | - Ning Li
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
- * E-mail: (YD); (NL)
| |
Collapse
|
6
|
O'Connor CJ, Cleverly DR, Butler PA, Walde P. Isolation and Characterization of Purified Bile Salt Stimulated Human Milk Lipase. J BIOACT COMPAT POL 2016. [DOI: 10.1177/088391159400900104] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A method has been developed for the isolation and purification of bile-salt-stimulated human milk lipase. This method yields up to six times more enzyme than other reported methods and the specific activity is compara ble. The concentration of BSSL recovered from the whole milk was 0.65 percent of the original protein content. The molecular weight of the isolated protein was 120 kDa. During the course of the purification, both protein content and specific activity were monitored and the esterase and lipase activities of the isolated product were characterized in the presence of sodium taurocholate. Five separate isolations were carried out with the introduction of minor varia tions in the procedure, but the catalytic properties of the product remain unchanged.
Collapse
Affiliation(s)
- Charmian J. O'Connor
- Department of Chemistry The University of Auckland Private Bag 92019 Auckland, New Zealand
| | - Douglas R. Cleverly
- Department of Chemistry The University of Auckland Private Bag 92019 Auckland, New Zealand
| | - Paul A.G. Butler
- Department of Chemistry The University of Auckland Private Bag 92019 Auckland, New Zealand
| | - Peter Walde
- Department of Chemistry The University of Auckland Private Bag 92019 Auckland, New Zealand
| |
Collapse
|
7
|
Lu J, Wang X, Zhang W, Liu L, Pang X, Zhang S, Lv J. Comparative proteomics of milk fat globule membrane in different species reveals variations in lactation and nutrition. Food Chem 2015; 196:665-72. [PMID: 26593540 DOI: 10.1016/j.foodchem.2015.10.005] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 09/29/2015] [Accepted: 10/01/2015] [Indexed: 10/23/2022]
Abstract
In present study, 312, 554, 175 and 143 proteins were identified and quantified by label-free quantitative proteomics in human, cow, goat and yak milk fat globule membrane (MFGM), respectively. Fifty proteins involved in vesicle mediate transport and milk fat globule secretion were conserved among species. Moreover, proteins involved in lipid synthesis and secretion (xanthine dehydrogenase/oxidase, stomatin and CD36), showed different expression pattern and the host defense proteins exhibited various profiles within species. Notably, the content and activity of lipid catabolic enzymes were significantly higher in human MFGM, which could be indicative of the superior fat utilization in breast fed infants. Our findings unraveled the significant differences in protein composition of human milk and conventionally used substitutes of it. The in-depth study of lipid metabolic enzymes in human MFGM will probably contribute to the improvement of the fat utilization through modulation of lipid catabolic enzymes in infant formula.
Collapse
Affiliation(s)
- Jing Lu
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xinyu Wang
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China; Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Weiqing Zhang
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Lu Liu
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiaoyang Pang
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Shuwen Zhang
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jiaping Lv
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China.
| |
Collapse
|
8
|
Behar DM, Basel-Vanagaite L, Glaser F, Kaplan M, Tzur S, Magal N, Eidlitz-Markus T, Haimi-Cohen Y, Sarig G, Bormans C, Shohat M, Zeharia A. Identification of a novel mutation in the PNLIP gene in two brothers with congenital pancreatic lipase deficiency. J Lipid Res 2013; 55:307-12. [PMID: 24262094 PMCID: PMC3886669 DOI: 10.1194/jlr.p041103] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Congenital pancreatic lipase (PNLIP) deficiency is a rare monoenzymatic form of exocrine pancreatic failure characterized by decreased absorption of dietary fat and greasy voluminous stools, but apparent normal development and an overall good state of health. While considered to be an autosomal recessive state affecting a few dozens of individuals world-wide and involving the PNLIP gene, no causative mutations for this phenotype were so far reported. Here, we report the identification of the homozygote missense mutation, Thr221Met [c.662C>T], in two brothers from a consanguineous family of Arab ancestry. The observed genotypes among the family members were concordant with an autosomal recessive mode of inheritance but moreover a clear segregation between the genotype state and the serum PNLIP activity was evident. Based on biophysical computational tools, we suggest the mutation disrupts the protein's stability and impairs its normal function. Although the role of PNLIP is well established, our observations provide genetic evidence that PNLIP mutations are causative for this phenotype.
Collapse
Affiliation(s)
- Doron M Behar
- Raphael Recanati Genetics Institute, Schneider Children's Medical Center of Israel, Rabin Medical Center, Petah Tikva, Israel
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Lindquist S, Andersson EL, Lundberg L, Hernell O. Bile salt-stimulated lipase plays an unexpected role in arthritis development in rodents. PLoS One 2012; 7:e47006. [PMID: 23071697 PMCID: PMC3469624 DOI: 10.1371/journal.pone.0047006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Accepted: 09/10/2012] [Indexed: 12/20/2022] Open
Abstract
OBJECTIVE The present study aimed to explore the hypothesis that bile salt-stimulated lipase (BSSL), in addition to being a key enzyme in dietary fat digestion during early infancy, plays an important role in inflammation, notably arthritis. METHODS Collagen-induced arthritis (CIA) and pristane-induced arthritis (PIA) in rodents are commonly used experimental models that reproduce many of the pathogenic mechanisms of human rheumatoid arthritis, i.e. increased cellular infiltration, synovial hyperplasia, pannus formation, and erosion of cartilage and bone in the distal joints. We used the CIA model to compare the response in BSSL wild type (BSSL-WT) mice with BSSL-deficient 'knock-out' (BSSL-KO) and BSSL-heterozygous (BSSL-HET) littermates. We also investigated if intraperitoneal injection of BSSL-neutralizing antibodies affected the development or severity of CIA and PIA in mice and rats, respectively. RESULTS In two consecutive studies, we found that BSSL-KO male mice, in contrast to BSSL-WT littermates, were significantly protected from developing arthritis. We also found that BSSL-HET mice were less prone to develop disease compared to BSSL-WT mice, but not as resistant as BSSL-KO mice, suggesting a gene-dose effect. Moreover, we found that BSSL-neutralizing antibody injection reduced both the incidence and severity of CIA and PIA in rodents. CONCLUSION Our data strongly support BSSL as a key player in the inflammatory process, at least in rodents. It also suggests the possibility that BSSL-neutralizing agents could serve as a therapeutic model to reduce the inflammatory response in humans.
Collapse
Affiliation(s)
- Susanne Lindquist
- Department of Clinical Sciences, Pediatrics, Umeå University, Umeå, Sweden.
| | | | | | | |
Collapse
|
10
|
|
11
|
Abstract
PURPOSE OF REVIEW To highlight our understanding of digestion and absorption of dietary lipids in newborn infants, and specifically how these processes differ from those in children and adults. RECENT FINDINGS The intestinal concentration of pancreatic triglyceride lipase (PTL) and bile salts is lower in newborns compared to later in life. Instead the PTL-related protein 2 and bile salt-stimulated lipase (BSSL) are the key enzymes secreted from pancreas, which in concerted action with gastric lipase operate to achieve efficient fat absorption during infancy. BSSL is also present in human milk which affects fat absorption and growth in breast-fed preterm infants. Under conditions of low luminal bile salt concentrations fat absorption is likely to occur from liquid crystalline product phases, which may result in absorption from an extended part of the small intestinal mucosal surfaces compared to adults. Chylomicron assembly and secretion also seem to adapt to the specific situation of the newborn. SUMMARY Both fat digestion and product absorption are different in newborn infants compared to adults; other lipases are used for digestion and different physical-chemical phases may be used for product absorption. Why these differences occur is still an unsolved question of considerable importance to neonatal nutrition.
Collapse
Affiliation(s)
- Susanne Lindquist
- Department of Clinical Sciences/Pediatrics, Umeå University, Umeå, Sweden.
| | | |
Collapse
|
12
|
Li X, Lindquist S, Lowe M, Noppa L, Hernell O. Bile salt-stimulated lipase and pancreatic lipase-related protein 2 are the dominating lipases in neonatal fat digestion in mice and rats. Pediatr Res 2007; 62:537-41. [PMID: 17805199 PMCID: PMC3488855 DOI: 10.1203/pdr.0b013e3181559e75] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
During infancy, the basic conditions for digestion of dietary fat differ from later in life. The bile salt-stimulated lipase (BSSL) is an enzyme expressed in the exocrine pancreas and in some species (including human) also in the lactating mammary gland and secreted with the milk. The aim of this study was to compare the ontogeny of four pancreatic lipases [BSSL, pancreatic triglyceride lipase (PL), pancreatic lipase-related protein 2 (PLRP2), and phospholipase A2 (PLA2)] in one species that supplies BSSL with milk (the mouse) and one that does not (the rat). We followed expression of the four pancreatic lipases from postnatal d 1 until after weaning in both species. We found that BSSL and PLRP2, two lipases with broad substrate specificity, dominated. It was not until weaning that significant expression of PL and PLA2 were induced. Thus, BSSL and PLRP2 seem to be responsible for fat digestion as long as milk is the main food. Moreover, the early temporal pattern of BSSL expression differed between species. We speculate that the milk-borne BSSL is able to compensate for a slower ontogeny of pancreatic BSSL expression in the mouse.
Collapse
Affiliation(s)
- Xiaonan Li
- Department of Clinical Sciences, Umeå University, SE-901 87 Umeå, Sweden
| | | | | | | | | |
Collapse
|
13
|
van Bennekum AM, Li L, Piantedosi R, Shamir R, Vogel S, Fisher EA, Blaner WS, Harrison EH. Carboxyl ester lipase overexpression in rat hepatoma cells and CEL deficiency in mice have no impact on hepatic uptake or metabolism of chylomicron-retinyl ester. Biochemistry 1999; 38:4150-6. [PMID: 10194331 DOI: 10.1021/bi981680+] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To study the role of carboxyl ester lipase (CEL) in hepatic retinoid (vitamin A) metabolism, we investigated uptake and hydrolysis of chylomicron (CM)-retinyl esters (RE) by rat hepatoma (McArdle-RH7777) cells stably transfected with a rat CEL cDNA. We also studied tissue uptake of CM-RE in CEL-deficient mice generated by targeted disruption of the CEL gene. CEL-transfected cells secreted active enzyme into the medium. However, both control and CEL-transfected cells accumulated exogenously added CM-RE or CM remnant (CMR)-derived RE in equal amounts. Serum clearance of intravenously injected CM-RE and cholesteryl ester were not different between wild-type and CEL-deficient mice. Also, the uptake of the two compounds by the liver and other tissues did not differ. These data indicate that the lack of CEL expression does not affect the uptake of dietary CM-RE by the liver or other tissues. Moreover, the percentage of retinol formed in the liver after CM-RE uptake, the levels of retinol and retinol-binding protein in serum, and retinoid levels in various tissues did not differ, indicating that CEL deficiency does not affect hepatic retinoid metabolism and retinoid distribution throughout the body. Surprisingly, in both pancreas and liver of wild-type, heterozygous, and homozygous CEL-deficient mice, the levels of bile salt-dependent retinyl ester hydrolase (REH) activity were similar. This indicates that in the mouse pancreas and liver an REH enzyme activity, active in the presence of bile salt and distinct from CEL, is present, compatible with the results from our accompanying paper that the intestinal processing and absorption of RE were unimpaired in CEL-deficient mice.
Collapse
Affiliation(s)
- A M van Bennekum
- Department of Biochemistry, MCP-Hahnemann School of Medicine, Philadelphia, Pennsylvania 19129, USA
| | | | | | | | | | | | | | | |
Collapse
|
14
|
Sahasrabudhe AV, Solapure SM, Khurana R, Suryanarayan V, Ravishankar S, deSousa SM, Das G. Production of recombinant human bile salt stimulated lipase and its variant in Pichia pastoris. Protein Expr Purif 1998; 14:425-33. [PMID: 9882578 DOI: 10.1006/prep.1998.0974] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
hBSSL and its truncated variant hBSSL-C cDNA clones were expressed in Pichia pastoris using two different signal peptides, native signal peptide and invertase signal peptide, respectively, to facilitate secretion of the recombinant proteins into the culture medium. Both recombinant proteins were secreted into the culture medium to a level of 45-50 mg/liter in shake flask cultures. Native signal peptide of hBSSL was recognized in P. pastoris and was cleaved at the same site as in humans. The level of expression of the hBSSL gene was found to be dependent on the number of its copies integrated into the host chromosome. The multicopy transformant clone was found to be very stable. When grown and induced in a fermentor, the level of accumulation of the recombinant hBSSL in the culture medium improved from 50 mg/liter in shake flask cultures to 300 mg/liter. The recombinant hBSSL purified from the culture supernatant was found to be similar to the native hBSSL in its biochemical properties except for the lectin-binding profile.
Collapse
Affiliation(s)
- A V Sahasrabudhe
- Astra Research Centre India, 18th Cross, Malleswaram, Bangalore, 560003, India
| | | | | | | | | | | | | |
Collapse
|
15
|
Nyberg L, Farooqi A, Bläckberg L, Duan RD, Nilsson A, Hernell O. Digestion of ceramide by human milk bile salt-stimulated lipase. J Pediatr Gastroenterol Nutr 1998; 27:560-7. [PMID: 9822324 DOI: 10.1097/00005176-199811000-00013] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
BACKGROUND There is a renewed interest in metabolism of sphingolipids because of their role in signal transduction. Sphingomyelin is the dominating phospholipid in human milk but its metabolism and possible function in the gastrointestinal tract of breast fed infants is unknown. We explored whether bile salt-stimulated milk lipase has a role in sphingolipid metabolism. METHODS In vitro assays of sphingomyelinase and ceramidase activities, using radiolabeled substrates, human milk samples and purified native and recombinant variants of bile salt-stimulated milk lipase with or without known activators or inhibitors. RESULTS Human whey and purified lipase catalysed hydrolysis of palmitoyl-labeled ceramide with the highest rate around pH 8.5-9.0. 1 mg of lipase hydrolysed 0.7 micromol ceramide in one hour at pH 8.5 in presence of 4 mM bile salt. The activity of whey was inhibited by antibodies towards human bile salt-stimulated milk lipase, indicating that this lipase accounted for virtually all ceramidase activity in the milk. In contrast, bile salt-stimulated milk lipase showed no activity against sphingomyelin. However we give evidence of a separate, hitherto unknown, acid sphingomyelinase in human milk. Under the used in vitro conditions this sphingomyelinase could account for hydrolysis of half of milk sphingomyelin in one hour. CONCLUSIONS Human milk bile salt-stimulated milk lipase hydrolyses ceramide and may thus have a role in sphingomyelin digestion, but only after initial hydrolysis to ceramide and phosphorylcholine. Part of the latter could be carried out in the stomach by the acid milk sphingomyelinase now described. We speculate that these two milk enzymes may be of importance for optimal use of human milk sphingolipids.
Collapse
Affiliation(s)
- L Nyberg
- Swedish Dairies' Association, Lund
| | | | | | | | | | | |
Collapse
|
16
|
Bläckberg L, Duan RD, Sternby B. Purification of carboxyl ester lipase (bile salt-stimulated lipase) from human milk and pancreas. Methods Enzymol 1997; 284:185-94. [PMID: 9379934 DOI: 10.1016/s0076-6879(97)84012-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- L Bläckberg
- Department of Physiological Chemistry, University of Umeå, Sweden
| | | | | |
Collapse
|
17
|
Strömqvist M, Törnell J, Edlund M, Edlund A, Johansson T, Lindgren K, Lundberg L, Hansson L. Recombinant human bile salt-stimulated lipase: an example of defective O-glycosylation of a protein produced in milk of transgenic mice. Transgenic Res 1996; 5:475-85. [PMID: 8840531 DOI: 10.1007/bf01980213] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The expression of recombinant human bile salt-stimulated lipase (bssl) was targeted to the lactating mammary gland of transgenic mice. Expression of recombinant genes comprising bsslcDNA, or alternatively genomic bssl DNA, under control of regulatory elements derived from the murine whey acidic protein (wap) gene was achieved and evaluated. Constructs containing genomic bssl sequences mediated high levels (0.5-1 mg ml-1) of recombinant human BSSL in the milk. The recombinant BSSL produced was purified, biochemically characterized and compared to native BSSL and recombinant BSSL produced in mouse C127 and hamster CHO cells. Recombinant BSSL derived from transgenic mice showed a different migration and distribution after SDS-PAGE electrophoresis, lower apparent molecular mass on size-exclusion chromatography and no detectable interactions with a panel of lectins. These results indicate a significantly lower degree of O-glycosylation of recombinant BSSL in milk from transgenic mice than was found for the native enzyme or recombinant CHO- or C127 cell-produced BSSL. Despite these differences, mouse-milk-derived recombinant BSSL exhibited similar lipase activity, the same stability to low pH and similar sensitivity to elevated temperatures as the native enzyme. The observation that mouse-C127-cell-produced recombinant BSSL is heavily O-glycosylated makes species-related restrictions less attractive as an explanation for the reduced O-glycosylation.
Collapse
|
18
|
Bläckberg L, Strömqvist M, Edlund M, Juneblad K, Lundberg L, Hansson L, Hernell O. Recombinant human-milk bile-salt-stimulated lipase. Functional properties are retained in the absence of glycosylation and the unique proline-rich repeats. EUROPEAN JOURNAL OF BIOCHEMISTRY 1995; 228:817-21. [PMID: 7737181 DOI: 10.1111/j.1432-1033.1995.tb20327.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Human milk bile-salt-stimulated lipase ensures efficient utilization of milk lipid in breast-fed infants. The N-terminal two-thirds of the peptide chain is highly conserved and shows striking similarities to typical esterases. In contrast, the remaining C-terminal part consists of a unique sequence of 16 proline-rich O-glycosylated repeats of 11 residues each. Recently we could show, using recombinant lipase variants, that neither these repeats nor the single N-linked sugar chain are essential for catalytic efficiency. In the present study, we report on the lack of importance of glycosylation and the unique repeats for other important functional properties, i.e. bile-salt activation, heparin binding, heat stability, stability at low pH and resistance to proteolytic inactivation. Compared to native enzyme, recombinant full-length lipase produced in two mammalian cell lines differed slightly in glycosylation pattern with no effects on the functional properties. Moreover, a variant lacking all repeats and the C-terminal tail following the last repeat exhibited the same functional characteristics as purified native milk enzyme. Thus, the structural basis for all the typical and functionally important properties reside in the N-terminal conserved part, in spite of the fact that none of these properties are shared by typical esterases. We could however, demonstrate that the C-terminal repeats are responsible for the unusual behaviour of the enzyme in size-exclusion chromatography, resulting in a considerably higher than expected apparent molecular mass.
Collapse
Affiliation(s)
- L Bläckberg
- Department of Medical Biochemistry and Biophysics, Umeå University, Sweden
| | | | | | | | | | | | | |
Collapse
|
19
|
O'Connor CJ, Cleverly DR. Fourier-transform infrared assay of bile salt-stimulated lipase activity in reversed micelles. JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY (OXFORD, OXFORDSHIRE : 1986) 1994; 61:209-214. [PMID: 7527225 DOI: 10.1002/jctb.280610305] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
A Fourier-transform infrared (FT-IR) spectroscopic method has been developed for assaying the bile salt-stimulated human milk lipase (BSSL, EC3.1) catalyzed hydrolysis of triolein in AOT reversed micelles in iso-octane. At 37 degrees C in 50 mmol dm-3 AOT the molar absorbtivities for the carbonyl stretching frequencies for triolein (at 1751 cm-1) and oleic acid (at 1714 cm-1) were 1646 dm3 mol-1 cm-1 and 743 dm3 mol-1 cm-1, respectively. The rate was linearly dependent upon the concentration of enzyme in the water pool up to 10 mg cm-3 and maximum activity was observed at a ratio (w0) of [H2O]:[AOT] = 16.7. Using these conditions, and in the presence of 10 mmol dm-3 sodium taurocholate (TC), the derived Michaelis-Menten parameters Vmax and Km were 57.5 mumol min-1 mg-1 and 5.53 mmol dm-3, respectively. These results are compared with those obtained in an oil-in-water microemulsion system and are discussed in terms of the relative partitioning of the enzyme and the substrate in the aqueous and oil phases and the interfacial concentration of the substrate in the two systems.
Collapse
Affiliation(s)
- C J O'Connor
- Department of Chemistry, University of Auckland, New Zealand
| | | |
Collapse
|
20
|
Abstract
In breast-fed infants, digestion of milk triglycerides, the major source of energy and long-chain polyunsaturated fatty acids, is catalyzed by a concerted action of gastric lipase, colipase-dependent pancreatic lipase, and bile salt-stimulated lipase (BSSL). The major part of BSSL is present in the milk and the lesser part originates in the infant's exocrine pancreas. Gastric lipase is important in initiating digestion of milk fat globule triglycerides in the stomach. BSSL shifts the final products of triglyceride digestion from monoglyceride and free fatty acid (the products of colipase-dependent pancreatic lipase) to glycerol and free fatty acid, which may promote efficient absorption. Moreover, BSSL is likely to promote efficient use of milk cholesteryl- and fat-soluble vitaminesters and long-chain polyunsaturated fatty acids (> C18). The cDNA sequence has shown that BSSL has a unique primary structure. The N-terminal half is highly conserved between species and shows striking homology to typical esterases, for example, acetylcholine esterase. In contrast, the C-terminal half, containing 16 proline-rich repeats of 11 amino acid residues, is unique to BSSL. Using several recombinant variants of BSSL, we have found that these unique repeats and the glycosylation are completely dispensable for activity. Thus all typical properties of BSSL reside in the N-terminal half of the molecule.
Collapse
Affiliation(s)
- O Hernell
- Department of Pediatrics, University of Umeå, Sweden
| | | |
Collapse
|
21
|
Hansson L, Bläckberg L, Edlund M, Lundberg L, Strömqvist M, Hernell O. Recombinant human milk bile salt-stimulated lipase. Catalytic activity is retained in the absence of glycosylation and the unique proline-rich repeats. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(19)74368-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
22
|
Bläckberg L, Hernell O. Bile salt-stimulated lipase in human milk. Evidence that bile salt induces lipid binding and activation via binding to different sites. FEBS Lett 1993; 323:207-10. [PMID: 8500612 DOI: 10.1016/0014-5793(93)81340-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Human milk bile salt-stimulated lipase ensures efficient triacylglycerol utilization in breast-fed newborns. For activity against long-chain triacylglycerol, primary bile salts are a prerequisite. Bile salts also protect the enzyme from inactivation by intestinal proteases. We have studied the effect of different bile salts on activation, protease protection, lipid binding, and enzyme inactivation, caused by an arginine modifying agent. Based on the results we propose a model involving two bile salt binding sites; one activation-site specific for primary bile salt, and another, less specific, lipid binding promoting site at which also secondary bile salt binds. Binding to this latter site induces binding of enzyme to emulsified substrates but binding promoting site at which also secondary bile salt binds. Binding to this latter site induces binding of enzyme to emulsified substrates but without subsequent lipolysis.
Collapse
Affiliation(s)
- L Bläckberg
- Department of Medical Biochemistry and Biophysics, University of Umeå, Sweden
| | | |
Collapse
|
23
|
Ellis LA, Hamosh M. Bile salt stimulated lipase: comparative studies in ferret milk and lactating mammary gland. Lipids 1992; 27:917-22. [PMID: 1491611 DOI: 10.1007/bf02535873] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Bile salt stimulated lipase (BSSL) activity is 10-20 times higher in ferret milk than in human milk. We have used the ferret to study BSSL activity in lactating mammary gland and in mammary cells isolated by hyaluronidase-collagenase treatment followed by Ficoll gradient centrifugation. Furthermore, we have compared the characteristics of BSSL in the tissue preparations (homogenate or cells) to BSSL of ferret milk and to BSSL purified from ferret and human milk. The characteristics of BSSL in ferret mammary gland preparations and milk were similar to those of human milk BSSL--absolute requirement of primary bile salts, pH optimum of 7.5-9.0, stability at pH 3-9 and inhibition by eserine (physostigmine) and by serum. Purified ferret milk BSSL had a lower molecular weight (90kD) than did human milk BSSL (125 kD). There was an 86% homology of the N-terminal amino acid sequence between BSSL of ferret and of human milk. The marked similarity in characteristics between BSSL in ferret and human milk and the high activity of BSSL in ferret milk (520 U/mL colostrum and 250 U/mL mature milk) indicate that this species is an ideal animal model for the study of the synthesis and secretion of this digestive lipase which constitutes a significant portion (1-2%) of total milk protein.
Collapse
Affiliation(s)
- L A Ellis
- Department of Pediatrics, Georgetown University Medical Center, Washington, D.C. 20007
| | | |
Collapse
|
24
|
Lidberg U, Nilsson J, Strömberg K, Stenman G, Sahlin P, Enerbäck S, Bjursell G. Genomic organization, sequence analysis, and chromosomal localization of the human carboxyl ester lipase (CEL) gene and a CEL-like (CELL) gene. Genomics 1992; 13:630-40. [PMID: 1639390 DOI: 10.1016/0888-7543(92)90134-e] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The gene encoding human carboxyl ester lipase (CEL), including 1628 bp of the 5'-flanking region, has been isolated and characterized from two overlapping lambda phage clones. The gene spans 9832 bp and contains 11 exons interrupted by 10 introns. The exons range in size from 88 to 204 bp, except for the last exon, which is 841 bp. A major and a minor transcription initiation site were determined 13 and 7 bp, respectively, upstream of the initiator methionine. The nucleotide sequence is identical with that of the previously reported cDNA, except for the third nucleotide in the 5'-untranslated sequence, a C, which in the cDNA is a T. A TAAATA sequence is present 26 nt upstream from the major CAP site, and within the 5'-flanking region there are several putative transcription factor binding sites. Seven Alu repetitive sequence elements are present in the region analyzed. The organization of the human CEL gene is similar to that of the recently reported rat pancreatic cholesterol esterase gene. The CEL gene was assigned to chromosome 9q34-qter, which confirms the recently reported results of Tayler et al. (1991, Genomics 10: 425-431). A previously unknown gene with a striking homology to the human CEL gene, here called the CEL-like gene (CELL), has also been isolated and characterized, including 1724 bp of the 5'-flanking region. The CELL gene, which most likely is a psuedogene, spans 4846 bp, and due to the absence of a 4.8-kb segment, the CEL gene exons 2-7 are not present in the CELL gene. Despite these differences, the CELL gene is transcribed. We have also assigned the CELL gene to a separate locus at chromosome 9q34-qter.
Collapse
Affiliation(s)
- U Lidberg
- Department of Molecular Biology, University of Göteborg, Sweden
| | | | | | | | | | | | | |
Collapse
|
25
|
Swan JS, Hoffman MM, Lord MK, Poechmann JL. Two forms of human milk bile-salt-stimulated lipase. Biochem J 1992; 283 ( Pt 1):119-22. [PMID: 1567358 PMCID: PMC1131002 DOI: 10.1042/bj2830119] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
This study provides the first direct evidence for the existence of two active forms of the human milk enzyme bile-salt-stimulated lipase. Heparin-based affinity chromatography and size-exclusion chromatography were used to obtain two active forms of this enzyme with molecular masses of 97 and 120 kDa.
Collapse
Affiliation(s)
- J S Swan
- Department of Chemistry, Bucknell University, Lewisburg, PA 17837
| | | | | | | |
Collapse
|
26
|
Strömqvist M, Holgersson J, Samuelsson B. Glycosylation of extracellular superoxide dismutase studied by high-performance liquid chromatography and mass spectrometry. J Chromatogr A 1991; 548:293-301. [PMID: 1939427 DOI: 10.1016/s0021-9673(01)88611-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Extracellular superoxide dismutase, EC-SOD, the main superoxide dismutase in biological fluids, is known from its lectin binding to be a glycoprotein. We have characterized the glycosylation of recombinant EC-SOD. A tryptic digest of the protein contained only one glycosylated peptide. This peptide was specifically bound to lectins and stained by periodic acid-Schiff stain. Although appearing very large on size-exclusion chromatography, it was shown to be glycosylated at only one site, asparagine-89, by specific cleavage with glycanases followed by mass spectrometry of the resulting peptide. Based on the binding properties of the peptide to concanavalin A and lentil lectin and the elution profile of N-glycanase-treated glycopeptide on ion-exchange chromatography, the carbohydrate appears to be the complex biantennary type with a core fucose.
Collapse
|
27
|
Nilsson J, Bläckberg L, Carlsson P, Enerbäck S, Hernell O, Bjursell G. cDNA cloning of human-milk bile-salt-stimulated lipase and evidence for its identity to pancreatic carboxylic ester hydrolase. EUROPEAN JOURNAL OF BIOCHEMISTRY 1990; 192:543-50. [PMID: 1698625 DOI: 10.1111/j.1432-1033.1990.tb19259.x] [Citation(s) in RCA: 107] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We have isolated and sequenced cDNA clones covering the entire coding sequence of human-milk bile-salt-stimulated lipase, as well as 996 nucleotides of the 3' end of the pancreatic enzyme carboxylic ester hydrolase. The deduced amino acid sequence of the lipase starts with a 23-residue leader peptide. The open reading frame continues with 722 amino acid residues. The sequence contains in the C-terminal part a proline-rich repeat, 16 repeats of 11 amino acid residues each. The mRNA was estimated to be approximately 2500 nucleotides from Northern blot and of similar size in mammary and pancreatic tissues. Data obtained indicate that the lipase and the carboxylesterase are identical and coded for by the same gene. The cDNA is 2428 bases long, which indicates that a near full-length copy of the transcript has been isolated. Comparisons with other enzymes show that the lipase is a new member of the supergene family of serine hydrolases. It is not only closely related (and in its N-terminal half virtually identical) to lysophospholipase from rat pancreas and cholesterol esterase from bovine pancreas, but also shows a high degree of similarity to several esterases, e.g. acetylcholine esterase. In contrast, no such similarity could be found to typical lipases.
Collapse
Affiliation(s)
- J Nilsson
- Department of Molecular Biology, University of Göteborg, Sweden
| | | | | | | | | | | |
Collapse
|
28
|
Lindström MB, Sternby B, Borgström B. Concerted action of human carboxyl ester lipase and pancreatic lipase during lipid digestion in vitro: importance of the physicochemical state of the substrate. BIOCHIMICA ET BIOPHYSICA ACTA 1988; 959:178-84. [PMID: 3349096 DOI: 10.1016/0005-2760(88)90029-x] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The pancreatic enzyme carboxyl ester lipase (CEL) has been shown to hydrolyse a large number of different esters, including triacylglycerols, cholesteryl esters and retinyl esters with an absolute requirement for bile salts. Some of the lipids that are substrates for CEL can also be hydrolysed by pancreatic lipase. In order to investigate the relative roles of human CEL and pancreatic lipase, the two enzymes were incubated on a pH-stat with isotope-labelled lipid substrate mixtures in physicochemical forms resembling the state of the dietary lipids in human intestinal contents. In the first set of experiments, cholesteryl oleate (CO) and retinyl palmitate (RP) were solubilised in an emulsion of triolein (TO) stabilised by egg phosphatidylcholine and bile salts. Lipase (always added together with its cofactor, colipase) hydrolysed TO, with monoolein and oleic acid as end-products, whereas CEL alone could not hydrolyse TO in the presence of phosphatidylcholine (PC). Lipase alone did not hydrolyse CO or RP, but CEL did hydrolyse these esters if lipase was present. Release of [3H]glycerol from labelled TO increased only slightly if CEL was added compared to lipase alone, suggesting that monoolein hydrolysis was slow under these conditions. In the second set of experiments, CO and RP were dissolved in bile salt/monoolein/oleic acid dispersions with varying bile salt concentrations. CEL hydrolysed CO and RP more rapidly in a system with a high bile salt concentration containing mixed micelles than in a system with a low bile salt concentration, where the lipids were dispersed in the form of mixed micellar and non-micellar aggregates; both types of aggregate have been reported to exist in human intestinal contents. In conclusion, these data suggest that the main function of CEL under physiological conditions is to hydrolyse cholesteryl and retinyl esters, provided that the triacylglycerol oil phase is hydrolysed by pancreatic lipase, which probably causes a transfer of the substrate lipids of CEL from the oil emulsion phase to an aqueous bile salt/lipolytic product phase. Depending on the bile salt/lipolytic product ratio, the substrate will reside in either micellar or non-micellar lipid aggregates, of which the micellar state is preferred by CEL.
Collapse
Affiliation(s)
- M B Lindström
- Department of Medical and Physiological Chemistry, University of Lund, Sweden
| | | | | |
Collapse
|
29
|
Tsujita T, Mizuno NK, Brockman HL. Nonspecific high affinity binding of bile salts to carboxylester lipases. J Lipid Res 1987. [DOI: 10.1016/s0022-2275(20)38580-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
30
|
Walde P, Sunamoto J, O'Connor CJ. Activity of bile-salt-stimulated human milk lipase in the presence of liposomes and mixed taurocholate-phosphatidylcholine micelles. BIOCHIMICA ET BIOPHYSICA ACTA 1987; 905:39-47. [PMID: 3676313 DOI: 10.1016/0005-2736(87)90006-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
(1) The interaction of bile-salt-stimulated human milk lipase and liposomal membranes has been investigated in the presence or absence of sodium taurocholate. Freshly purified enzyme enhances the permeability of liposomal membranes but thermally inactivated enzyme does not. (2) The ability of the enzyme to catalyze the hydrolysis of a relatively hydrophilic substrate, 4-nitrophenyl acetate, and a more hydrophobic substrate, 4-nitrophenyl palmitate, has also been measured in media containing small unilamellar vesicles of egg phosphatidylcholine in both the absence and presence of taurocholate, and also in the presence of free taurocholate in the absence of liposomes. (3) The enzyme-catalyzed hydrolysis of 4-nitrophenyl acetate is enhanced in all of these systems, but 4-nitrophenyl palmitate is protected from enzymic attack in the phosphatidylcholine-bile salt systems. If free taurocholate be present in the system before 4-nitrophenyl palmitate is added, then, and only then, is enzymic activity observed. (4) These results have been interpreted in terms of the importance of the microenvironment around the substrate and the role played by the bile salt surfactant in stimulating the enzyme.
Collapse
Affiliation(s)
- P Walde
- Department of Industrial Chemistry, Faculty of Engineering, Nagasaki University, Japan
| | | | | |
Collapse
|
31
|
O'Connor CJ, Sutton BM. Interfacial interactions between proteins and mammalian lipases. Adv Colloid Interface Sci 1987; 28:1-34. [PMID: 3333136 DOI: 10.1016/0001-8686(87)80007-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The effects of proteins, both endogenous and exogenous, on the activity of lipases against water soluble and water insoluble substrates have been reviewed. The enzymes considered are pancreatic and gastric lipases, and lipoprotein, bile-salt-stimulated human milk and pancreatic carboxyl ester lipases. A brief account is given of the function of each enzyme and of the physical properties of the interacting proteins, which include albumins, lysozymes, globulins and immunoglobulins, myoglobin, transferrins, alpha-lactalbumin and melittin. With few exceptions (for example, the effect of colipase on pancreatic lipase), the interaction of proteins with lipases which act at the lipid-water interface of water insoluble substrates results in deactivation of enzymic activity. It seems that the amphiphilic nature of proteins allows them to aggregate at interfaces, thereby altering the nature of the interface and decreasing accessibility of the substrate to the enzyme. This discussion gives consideration to association of the proteins with the enzyme or the interface and to whether the interactions with specific binding sites or interfacial inactivation are responsible for the observations. However, the effect of proteins on lipases acting against water soluble substrates varies from protein to protein. Activation of enzyme-activity occurs if the interacting proteins are able to act as acyl transfer agents and thus introduce another catalytic hydrolysis pathway into the reaction mechanism. Inhibition may be caused by specific interactions between the protein and the enzyme or the substrate.
Collapse
Affiliation(s)
- C J O'Connor
- Department of Chemistry, University of Auckland, New Zealand
| | | |
Collapse
|
32
|
Pamblanco M, Ten A, Comín J. Bile salt-stimulated lipase activity in human colostrum from mothers of infants of different gestational age and birthweight. ACTA PAEDIATRICA SCANDINAVICA 1987; 76:328-31. [PMID: 3591299 DOI: 10.1111/j.1651-2227.1987.tb10469.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The bile salt-stimulated lipase (BSSL) activity was measured in milk collected at 3-4 days postpartum (colostrum) from 36 mothers divided into three groups according to gestational age and birthweight of their infants. BSSL activity changed with the length of gestation. Preterm colostrum presented a mean activity significantly higher than the term groups (small-for-gestational age and appropriate-for-gestational age) which had similar values. The ratio of BSSL activity to the estimated fat content was 6.33 in colostrum of mothers who delivered preterm and 4.20 in colostrum of both groups of term mothers. These data suggest that preterm colostrum has a higher fat digesting potential than term colostrum and that it is the gestational age rather than the adequacy or non-adequacy of birthweight to gestational age that may influence the BSSL activity.
Collapse
|
33
|
Chappell JE, Clandinin MT, McVey MA, Chance GW. Free fatty acid content of human milk: physiologic significance and artifactual determinants. Lipids 1985; 20:216-21. [PMID: 4039783 DOI: 10.1007/bf02534191] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Analysis of human milk was conducted to determine if free fatty acids occur naturally or as a consequence of artifactual lipolysis after milk expression. Five mothers provided triplicate early morning milk samples on day 43 of lactation. Following extraction, lipid classes were separated by preparative thin layer chromatography and quantified by capillary gas liquid chromatography. Fresh milk samples collected with 20 volumes chloroform-methanol (1:1, v/v) were analogous in total free fatty acid level and profile of fatty acids to a duplicate sample collected with 0.4M EDTA and immediately frozen at -10 C. Low milk levels of free fatty acids appear to exist naturally. During days 4-37 of lactation, four serial milk samples from 15 mothers were collected and frozen with 0.4M EDTA. The concentration of free fatty acids in colostrum (0.03-0.5%, w/w) was lower than for subsequent days (0.3-2.5%, w/w). Additional samples were collected with and without a lipase inhibitor (0.4M EDTA) and subjected to routine collection and storage procedures. Significantly different fatty acid profile and higher levels of free fatty acids in milk collected without a lipase inhibitor added indicate that domestic freezing and/or thawing ruptures the fat globule membrane, allowing sn-1-stereospecific serum stimulated lipoprotein lipase contact with its triglyceride substrate. Standard procedures for collection of human milk for gavage fed infants appears to stimulate artifactual lipolysis of milk triglyceride and subsequent release of free fatty acids. The proposed relationship between dietary free fatty acids and prolonged, unconjugated hyperbilirubinemia in the newborn is discussed with regard to the significance of preintestinal lipolysis.
Collapse
|
34
|
|
35
|
Studies in bile salt solutions. VI. Micellar catalysis of ester hydrolysis by bile-salt-stimulated human milk lipase. J Colloid Interface Sci 1984. [DOI: 10.1016/0021-9797(84)90258-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
36
|
Characteristics and benefits of bile salt-stimulated lipase in human milk. Nutr Rev 1984; 42:372-3. [PMID: 6396544 DOI: 10.1111/j.1753-4887.1984.tb02265.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
|
37
|
O'Connor CJ, Wallace RG. Studies in bile salt solutions. Deoxycholate stimulation of human milk lipase. FEBS Lett 1984; 170:375-7. [PMID: 6723969 DOI: 10.1016/0014-5793(84)81347-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Stimulation of human milk lipase by deoxycholate and its taurine and glycine conjugates was demonstrated by measuring the esterolysis reaction of 4-nitrophenylacetate. The steroidal surfactants did not bind strongly to the polar substrate but they did bind effectively to a hydrophobic site on the enzyme and these bile salt-enzyme complexes were effective catalysts. These results are compared with those for stimulation of the enzyme by cholate surfactants and it has been demonstrated that the absence of a 7 alpha-OH substituent on the steroid nucleus does not prevent stimulation of either the esterolytic or lipolytic activity of the enzyme.
Collapse
|