Purification and characterization of chymotrypsins from the hepatopancreas of crucian carp (Carassius auratus)

LC-MS/MS based characterisation and differential expression of proteins in Himalayan snow trout, Schizothorax labiatus using LFQ technique

Molecular characterization of fish muscle proteins are nowadays considered as a key component to understand the role of specific proteins involved in various physiological and metabolic processes including their up and down regulation in the organisms. Coldwater fish specimens including snow trouts hold different types of proteins which help them to survive in highly diversified temperatures fluctuating from 0 to 20 °C. So, in current study, the liquid chromatography mass spectrometry using label free quantification technique has been used to investigate the muscle proteome profile of Schizothorax labiatus. For proteomic study, two weight groups of S. labiatus were taken from river Sindh. The proteomic analysis of group 1 revealed that a total of 235 proteins in male and 238 in female fish were recorded. However, when male and female S. labiatus were compared with each other on the basis of spectral count and abundance of peptides by ProteinLynx Global Server software, a total of 14 down-regulated and 22 up-regulated proteins were noted in this group. The highly down-regulated ones included homeodomain protein HoxA2b, retinol-binding protein 4, MHC class II beta chain and proopiomelanocortin while as the highly expressed up-regulated proteins comprised of gonadotropin I beta subunit, NADH dehydrogenase subunit 4, manganese superoxide dismutase, recombinase-activating protein 2, glycosyltransferase, chymotrypsin and cytochrome b. On the other hand, the proteomic characterisation of group 2 of S. labiatus revealed that a total of 227 proteins in male and 194 in female fish were recorded. When male and female S. labiatus were compared with each other by label free quantification, a total of 20 down-regulated and 18 up-regulated proteins were recorded. The down-regulated protein expression of group 2 comprised hepatic lipase, allograft inflammatory factor-1, NADH dehydrogenase subunit 4 and myostatin 1 while the highly expressed up-regulated proteins included glycogen synthase kinase-3 beta variant 2, glycogen synthase kinase-3 beta variant 5, cholecystokinin, glycogen synthase kinase-3 beta variant 3 and cytochrome b. Significant (P < 0.05) difference in the expression of down-regulated and up-regulated proteins was also noted between the two sexes of S. labiatus in each group. According to MS analysis, the proteins primarily concerned with the growth, skeletal muscle development and metabolism were down-regulated in river Sindh, which indicates that growth of fish during the season of collection i.e., winter was slow owing to less food availability, gonad development and low metabolic activity. While, the proteins related to immune response of fish were also noted to be down-regulated thereby signifying that the ecosystem has less pollution loads, microbial, pathogenic and anthropogenic activities. It was also found that the proteins involved in glycogen metabolism, reproductive and metabolic processes, particularly lipid metabolism were up-regulated in S. labiatus. The significant expression of these proteins may be connected to pre-spawning, gonad development and use of stored food as source of energy. The information generated in this study can be applied to future research aimed at enhancing food traceability, food safety, risk management and authenticity analysis.

Cromatografía de interacción hidrofóbica como método de separación de proteasas alcalinas de vísceras de Scomberomorus sierra

Este estudio se enfocó en recuperar proteasas alcalinas de vísceras de Scomberomorus sierra  mediante cromatografía de interacción hidrofóbica. Tres proteasas alcalinas se lograron separar parcialmente usando esta técnica cromatográfica; dos de ellas con pesos moleculares de 19 y 31 kDa fueron identificadas como enzimas tipo tripsina de acuerdo a ensayos de inhibición. La proteasa alcalina con peso molecular de 31 kDa, única enzima aislada, fue purificada bajo las siguientes condiciones cromatográficas: sulfato de amonio l3% (p/v) y etilenglicol al 27% (p/v); esta enzima mostró actividad máxima a pH 9 – 10 y 50 – 60 °C y fue fuertemente inhibida por el inhibidor de tripsina de soya (SBTI) como por el inhibidor de tripsina porcina (TPI). Una tercera proteasa alcalina con peso molecular de 20 kDa fue parcialmente separada e inhibida por tosil fenilalanil clorometil cetona (TPCK), la cual mostró actividad óptima a pH 9 – 11 y 60 °C. Estos resultados muestran que las vísceras de Scomberomorus sierra podrían ser de utilidad como fuente de proteasas.

Chymotrypsin isolation from jumbo squid (Dosidicus gigas) hepatopancreas: Partial characterization and effect on muscle collagen

Chymotrypsin was purified from jumbo squid hepatopancreas (HP) with 2.4-fold and yield 1.9%, and characterized with a molecular weight of 31 kDa, as estimated by sodium dodecyl sulfatepolyacrylamide gel electrophoresis (SDS-PAGE). Chymotrypsin effect over collagen extracted from the mantle, fins and arms of the jumbo squid was evaluated. The enzyme exhibited the maximum activity at pH 7 and 65°C using Suc-Ala-Ala-Pro-Phe-p-nitroanilide (SAAPNA) as a substrate and it was identified using the specific inhibitors N-tosyl-L-phenylalaninechloromethyl ketone (TPCK) and phenyl methyl sulfonyl fluoride (PMSF), showing residual activities of 6% and 0%, respectively. Furthermore, high activity was observed in the pH range of 4.0 to 8.0. Purified enzyme showed a moderate in vitro activity using muscle collagen as a substrate. Although further research is needed, the results suggest that the enzyme has a potential application where acidic or slightly alkaline conditions are needed.

Cathepsin L is an immune-related protein in Pacific abalone (Haliotis discus hannai)--Purification and characterization

Cathepsin L, an immune-related protein, was purified from the hepatopancreas of Pacific abalone (Haliotis discus hannai) by ammonium sulfate precipitation and column chromatographies of SP-Sepharose and Sephacryl S-200 HR. Purified cathepsin L appeared as two bands with molecular masses of 28.0 and 28.5 kDa (namely cathepsin La and Lb) on SDS-PAGE under reducing conditions, suggesting that it is a glycoprotein. Peptide mass fingerprinting (PMF) analysis revealed that peptide fragments of 95 amino acid residues was high similarity to cathepsin L of pearl oyster (Pinctada fucata). The optimal temperature and pH of cathepsin L were 35 °C and pH 5.5. Cathepsin L was particularly inhibited by cysteine proteinase inhibitors of E-64 and leupeptin, while it was activated by metalloproteinase inhibitors EDTA and EGTA. The full-length cathepsin L cDNA was further cloned from the hepatopancreas by rapid PCR amplification of cDNA ends (RACE). The open reading frame of the enzyme was 981 bp, encoding 327 amino acid residues, with a conserved catalytic triad (Cys134, His273 and Asn293), a potential N-glycosylation site and conserved ERFNIN, GNYD, and GCGG motifs, which are characteristics of cathepsin L. Western blot and proteinase activity analysis revealed that the expression and enzyme activity of cathepsin L were significantly up-regulated in hepatopancreas at 8 h following Vibrio parahaemolyticus infection, demonstrating that cathepsin L is involved in the innate immune system of abalone. Our present study for the first time reported the purification, characterization, molecular cloning, and tissue expression of cathepsin L in abalone.

A chymotrypsin from the Digestive Tract of California Spiny Lobster, Panulirus interruptus: Purification and Biochemical Characterization

A chymotrypsin was purified from the gastric juice of California spiny lobster (Panulirus interrutpus), using preparative electrophoresis and affinity chromatography on agarose-p-aminobenzamidine. The molecular mass was estimated by polyacrylamide gel electrophoresis (SDS-PAGE) under denaturing conditions to be 28 kDa. Chymotrypsin activity was totally inhibited by phenylmethylsulfonyl fluoride (PMSF) and chymostatin. Lobster chymotrypsin had optimal pH 7.0-8.0 and temperature of 55 °C. The enzyme is highly stable under a wide range of pH (retaining up to 80 % of activity after 1 h of incubation at pH 3.0, 5.0, and 12.0), showing higher stability at pH 8.0, and was inactivated after 20 min at 55 °C. Lobster chymotrypsin was able to hydrolyze protein substrates at as low as pH 3.0. These results are consistent with the findings of enzyme stability. Activity was assessed after incubation of enzyme with different organic solvents (in the range of 10-50 %); when tested in the presence of acetone, ethanol, propanol, and butanol, lobster chymotrypsin residual activity was >80 %; whereas in the presence of dimethyl sulfoxide (DMSO) and toluene, lobster chymotrypsin residual activity was <80 %. Deduced amino acid sequence, corroborated by mass spectrometry, was determined.

Purification and characterization of chymotrypsin from viscera of vermiculated sailfin catfish, Pterygoplichthys disjunctivus, Weber, 1991

Pterygoplichthys disjunctivus viscera chymotrypsin was purified by fractionation with ammonium sulfate (30-70 % saturation), gel filtration, affinity, and ion exchange chromatography. Chymotrypsin molecular weight was approximately 29 kDa according to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), shown a single band in zymogram. Electrofocusing study suggested being an anionic enzyme (pI ≈ 3.9), exhibiting maximal activity at pH 9 and 50 °C, using Suc-Ala-Ala-Pro-Phe-p-nitroanilide (SAAPNA) as substrate. Enzyme was effectively inhibited by phenyl methyl sulfonyl fluoride (PMSF) (99 %), and N-tosyl-L-phenylalanine chloromethyl ketone (TPCK) (94 %). Enzyme activity was affected by the following ions in decreasing order: Hg(2+), Fe(2+), Cu(2+), Li(1+), Mg(2+), K(1+), Mn(2+), while Ca(2+) had no effect. Chymotrypsin activity decreased continuously as NaCl concentration increased (from 0 to 30 %). K m and V max values were 0.72 ± 1.4 mM and 1.15 ± 0.06 μmol/min/mg of protein, respectively (SAAPNA as substrate). Results suggest the enzyme has a potential application where low processing temperatures are needed, such as in fish sauce production.

Identification of physicochemical properties of Scylla paramamosain allergen, arginin kinase

BACKGROUND

Arginine kinase (AK) is expressed in a wide variety of species, including human food sources (seafood) and pests (cockroaches and moths), and has been reported as a novel allergen. However, there has been little research on the allergenicity of AK in crustaceans. In this study the physicochemical properties of AK from mud crab (Scylla paramamosain) were investigated.

RESULTS

Analysis by sodium dodecyl sulfate polyacrylamide gel electrophoresis, immunoblotting and inhibition enzyme-linked immunosorbent assay revealed that purified AK was unstable in thermal processing and in acid buffer. Under simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) conditions, purified AK was much more readily degraded by pepsin than by trypsin or chymotrypsin. The unpurified AK in crab myogen degraded more markedly than purified AK. In addition, in two-phase gastrointestinal digestion, AK was rapidly degraded by pepsin but resistant to trypsin and chymotrypsin digestion, while tropomyosin derived from mud crab was resistant to pepsin digestion but digested readily by trypsin or chymotrypsin. Further study of serum samples obtained from crab-allergic human patients indicated that the allergenicity of AK was markedly reduced by digestion with SGF but not SIF.

CONCLUSION

AK is an important food allergen despite its unstable physicochemical properties of digestibility.

A new chymotrypsin-like serine protease involved in dietary protein digestion in a primitive animal, Scorpio maurus: purification and biochemical characterization

Background

Most recent works on chymotrypsins have been focused on marine animals and insects. However, no study was reported in chelicerate.

Results

Scorpion chymotrypsin-like protease (SCP) was purified to homogeneity from delipidated hepatopancreases. The protease NH₂-terminal sequence exhibited more than 60% monoacids identity with those of insect putative peptidases. The protease displayed no sequence homology with classical proteases. From this point of view, the protease recalls the case of the scorpion lipase which displayed no sequence homology with known lipases. The scorpion amylase purified and characterized by our time, has an amino-acids sequence similar to those of mammalian amylases. The enzyme was characterized with respect its biochemical properties: it was active on a chymotrypsin substrate and had an apparent molecular mass of 25 kDa, like the classically known chymotrypsins. The dependence of the SCP activity and stability on pH and temperature was similar to that of mammalian chymotrypsin proteases. However, the SCP displayed a lower specific activity and a boarder pH activity range (from 6 to 9).

Conclusion

lower animal have a less evaluated digestive organ: a hepatopancreas, whereas, higher ones possess individualized pancreas and liver. A new chymotrypsin-like protease was purified for the first time from the scorpion hepatopancreas. Its biochemical characterization showed new features as compared to classical chymotrypsin-higher-animals proteases.

Alkaline chymotrypsin from striped seabream (Lithognathus mormyrus) viscera: purification and characterization

An alkaline chymotrypsin from the intestine of striped seabream (Lithognathus mormyrus) was purified by precipitation with ammonium sulfate, Sephadex G-100 gel filtration, Mono Q-Sepharose anion-exchange chromatography, ultrafiltration, second Sephadex G-100 gel filtration, and a second Mono Q-Sepharose anion-exchange chromatography with a 80-fold increase in specific activity. The molecular weight of the purified alkaline chymotrypsin was estimated to be 27 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and size exclusion chromatography. The enzyme was highly active over a wide range of pH from 7.0 to 12.0, with an optimum at pH 10.0-11.0 using succinyl-L-ala-ala-pro-l-phenylalanine-p-nitroanilide (SAAPNA) as a substrate. The relative activities at pH 7.0 and 12.0 were about 66% and 45.5%, respectively. Further, the enzyme was extremely stable over a broad pH range (6.0-12.0). The optimum temperature for enzyme activity was 50 degrees C, and the enzyme displayed higher enzyme activity at low temperatures when compared to other enzymes. The purified enzyme was strongly inhibited by soybean trypsin inhibitor (SBTI) and phenylmethylsulfonyl-fluoride (PMSF), a serine protein inhibitor, and N-toluenesulfonyl-L-lysine chloromethyl ketone (TLCK), a chymotrypsin specific inhibitor. The N-terminal amino acid sequence of the first nine amino acids was IVNGEEAVP. The chymotrypsin kinetic constants, Km and kcat on SAAPNA as a substrate, were 30.7 microM and 14.35 s(-1), respectively, while the catalytic efficiency kcat/Km was 0.465 microM(-1) s(-1). The high activity at high alkaline pH and low temperatures make this protease a potential candidate for future use in detergent processing industries.

Biochemical characterization of chymotrypsins from the hepatopancreas of Japanese sea bass (Lateolabrax japonicus)

Two chymotrypsins (chymotrypsins A and B) have been purified to homogeneity from the hepatopancreas of Japanese sea bass ( Lateolabrax japonicus ) by ammonium sulfate fractionation and chromatographies on DEAE-Sepharose and Phenyl-Sepharose. Two-dimensional electrophoresis (2-DE) analysis revealed that the molecular masses of chymotrypsins A and B were approximately 27.0 and 27.5 kDa, respectively. Their respective isoelectric points were 8.0 and 7.0. Purified chymotrypsins also revealed a single band on native-PAGE, whereas their mobilities were quite different. Optimum temperature and pH of chymotrypsins A and B were 45 degrees C and 8.0, respectively. Both enzymes were strongly inhibited by chymostatin, phenylmethanesulfonyl fluoride (PMSF), and Pefabloc SC, but slightly inhibited by metalloproteinase inhibitor of 1,10-phenanthroline and EDTA. Using Suc-Leu-Leu-Val-Tyr-MCA as substrate, apparent K(m) values of chymotrypsins A and B were 0.8 and 1.1 microM and k(cat) values were 2.7 and 2.0 s(-1), respectively. The N-terminal amino acid sequences of chymotrypsins A and B were determined to the 21st and 18th residues, respectively, and were identical. These sequences exhibited high identities to chymotrypsins from other animals. The digestive effect of the two chymotrypsins on myofibrillar proteins indicated their effectiveness in the degradation of food proteins.