Properties of the amylase produced in carcinoma of the lung

Heat, Acid and Chemically Induced Unfolding Pathways, Conformational Stability and Structure-Function Relationship in Wheat α-Amylase

Wheat α-amylase, a multi-domain protein with immense industrial applications, belongs to α+β class of proteins with native molecular mass of 32 kDa. In the present study, the pathways leading to denaturation and the relevant unfolded states of this multi-domain, robust enzyme from wheat were discerned under the influence of temperature, pH and chemical denaturants. The structural and functional aspects along with thermodynamic parameters for α-amylase unfolding were probed and analyzed using fluorescence, circular dichroism and enzyme assay methods. The enzyme exhibited remarkable stability up to 70°C with tendency to aggregate at higher temperature. Acid induced unfolding was also incomplete with respect to the structural content of the enzyme. Strong ANS binding at pH 2.0 suggested the existence of a partially unfolded intermediate state. The enzyme was structurally and functionally stable in the pH range 4.0–9.0 with 88% recovery of hydrolytic activity. Careful examination of biophysical properties of intermediate states populated in urea and GdHCl induced denaturation suggests that α-amylase unfolding undergoes irreversible and non-coincidental cooperative transitions, as opposed to previous reports of two-state unfolding. Our investigation highlights several structural features of the enzyme in relation to its catalytic activity. Since, α-amylase has been comprehensively exploited for use in a range of starch-based industries, in addition to its physiological significance in plants and animals, knowledge regarding its stability and folding aspects will promote its biotechnological applications.

Multiple myeloma associated with sialyl salivary-type amylase

BACKGROUND

There have been several reports describing a notable hyperamylasaemia in patients with multiple myeloma. Such amylase-producing myelomas have been mainly described in the context of concomitant salivary-type hyperamylasaemia, with sialyl salivary-type amylase identified in a portion of those cases. We investigated the incidence of the production of sialyl salivary-type amylase in serum of multiple myeloma patients.

METHODS

Eleven patients (6 male and 5 female) who had been diagnosed as having multiple myeloma were enrolled in this study. Sialyl salivary-type amylase was detected by isoamylase electrophoresis and HPLC analysis, and identified by detecting either abnormal neuraminidase-sensitive band through isoamylase electrophoresis or abnormal extra-elution peak of amylase by means of HPLC analysis.

RESULTS

Sialyl salivary-type amylase was detected in 7 out of 11 (63.6%) patients. Median total amylase activity was 154 U/l (range 109-43020). Isoamylase electrophoretic patterns of patients' serum were normal in 5 patients (71.4%) out of 7 patients and salivary-dominant in 2 (50.0%) out of 4 patients.

CONCLUSIONS

We consider that there is no significant relationship between total serum amylase level and amylase isoenzyme pattern in the incidence of production of sialyl salivary-type amylase with multiple myeloma.

Expression of alpha-amylase gene in rat liver: liver-specific amylase has a high affinity to glycogen

The reactivity of rat liver alpha-amylases with maltotriose (G3), maltopentose (G5) and glycogen has been investigated. Liver amylases were found to be glycosylated and to have a molecular mass of 50 kDa by Western blotting using an anti-human salivary amylase antibody. The glycosylated liver amylases were found to be capable of G3- and G5-hydrolysis and of glucose formation, as demonstrated by thin-layer chromatography. When the amylase preparation was exposed to different concentrations of glycogen and run on a cellulose acetate membrane, the mobilities of rat liver amylases significantly decreased with tailing directly from the point of origin. In contrast, rat salivary amylases were not so much. These results indicate that rat liver amylases have a strong affinity to glycogen. We confirmed the expression of liver-specific amylases in rat liver by reverse transcriptional-polymerase chain reaction (RT-PCR); PCR products showed one band of an expected size of 474 bp using primers tested in the present study. A partial nucleotide sequence was then determined. When compared with the gene of mouse liver amylase, the substitution of 26 bases out of 434 bases was elucidated. The present data demonstrate the presence of liver-specific amylases in rats.

Glycosylated salivary alpha-amylases are capable of maltotriose hydrolysis and glucose formation

The physiological and/or clinical significance of sugar chains in human salivary alpha-amylase was investigated in terms of substrate-specificity for synthesized malto-oligosaccharides. Glycosylated and non-glycosylated alpha-amylases were prepared on a Sephacryl S-200 column, in which the amylases were separated into four fractions from the different affinities for Sephacryl: fraction I, amylases bearing sugar chains with sialic acid; fraction II, amylases bearing sugar chains without sialic acid; fractions III and IV, non-glycosylated amylases. These were classified according to the differences in their affinities for lectins, molecular sizes and isoelectric points. The inhibitory effect of maltotriose (G3) on starch hydrolysis of the amylase fraction, suggests that starch and G3 can be the substrate for glycosylated amylase, and that the glycosylated amylases are capable of G3 hydrolysis for conversion into maltose and glucose. Using malto-oligosaccharides, G3, G4, G5 and G7, as substrates, the substrate-specificities and G3/G5 ratio of amylase activities in the four fractions were examined. Maltopentaose, G5, is routinely used as a substrate for alpha-amylase, and then we assumed that both glycosylated and non-glycosylated amylases react with G5. Moreover, the results indicate that the glycosylated amylases clearly had a higher capacity for G3 hydrolysis than the non-glycosylated amylases, although no substrate preference of either type of amylase was observed among G4, G5 and G7. Glycosylated amylases have the capacity for glucose formation from malto-oligosaccharides.

Utilization of enzyme-substrate interactions in analytical chemistry

Enzymes are capable of a highly specific interaction with a variety of substances including their respective substrates. This review summarizes how such interactions may be used in analytical (bio-)chemistry, e.g., for the elucidation of the binding mechanism, the determination of the binding strength, the carting of the binding site, or the screening of possible substrate/inhibitor molecules. Possible assay formats such as analytical affinity chromatography, affinity capillary electrophoresis (ACE), conventional affinity gel electrophoresis (AEP), and related techniques are discussed together with examples of recent applications. In addition a brief section on enzyme-substrate reactions as tools in analytical chemistry is included, since these are perhaps even more important to analytical (bio-)chemistry. The development and application of bioanalytical systems and especially biosensors in various fields including medicine, biotechnology, agriculture, defense and foodstuffs are considered.

Affinity electrophoresis and its applications to studies of immune response

Affinity electrophoresis (AEP) is a useful technique for separation of biomolecules such as plasma proteins, enzymes, nucleic acids, lectins, receptors, and extracellular matrix proteins by specific interactions with their ligands in electric fields and for the determination of dissociation constants for those interactions. Two-dimensional affinity electrophoresis (2-D AEP), which was newly developed by a combination of isoelectric focusing with AEP, has been used for studies on immune response to haptens. Antihapten antibodies, which were induced by immunization of a mouse with the hapten-conjugated bovine serum albumin, were separated by 2-D AEP into a large number of groups of IgG spots with a few microliters of antiserum. Each group of spots showed an identical affinity for the hapten but different isoelectric points as in the case of monoclonal antibodies specific to the hapten. This enabled us to study the diversification and affinity maturation of antihapten antibodies in the course of immunization of a single mouse. Furthermore, effects of a carrier and a hapten array on the production of antihapten antibodies and the cause of charge heterogeneity of monoclonal antibodies were also examined to understand the molecular basis of the immune response in vivo.

Hydrolases acting on glycosidic bonds: chromatographic and electrophoretic separations

We describe analyses of unusual human alpha-amylase, performed in our laboratory and review available methods for amylase study. Electrophoretic and chromatographic methods provide an effective means for the analysis of amylase isoenzymes and unusual amylase. The recent identification of a selective inhibitor and a monoclonal antibody to amylase isoenzyme contributes to rapid routine clinical assays of amylase isoenzymes. However unusual amylases such as variants, macroamylasemia and sialyl salivary-type amylasemia cannot be detected by those conventional methods. The unusual amylases can only be detected by electrophoresis and can be easily characterized by combination study with chromatographic methods. Electrophoretic and chromatographic methods are universal means to validate unusual amylases found in patient sera. Further basal studies are needed to define the roles of salivary amylase in exocrine fluids using those separation techniques.

Separation and characterization of sialic acid-containing salivary-type amylase from patients' sera with immunoglobulin A-type myeloma

Isoamylases, with an abnormal anodic migration, were detected by an electrophoretic technique in the sera from two patients with immunoglobulin A-type myeloma. The abnormal isoamylase bands migrate towards the anode faster than the salivary isoamylase (S2) band and were stained more strongly than the S2 sub-band. The abnormal isoamylase could be separated from patients' sera by using size-exclusion high-performance liquid chromatography. The serum abnormal isoamylases were showed to be sialic acid residues containing amylase, after the study of treatment with neuraminidase (EC 3.2.1.18), and to be salivary-type amylase, after the study of reaction with human salivary monoclonal antibody. The abnormal bands were not detected in the saliva from one patient. The two patients had no detectable malignancies except myeloma. These findings strongly suggest that the sialic acid-containing salivary-type amylases were produced ectopically from myeloma cells. In this regard the ectopic amylase production by myeloma cells is discussed.

Electrophoretic characterization of posttranslational modifications of human parotid salivary alpha-amylase

Human salivary alpha-amylase displays multiple bands upon native polyacrylamide gel electrophoresis. In fresh saliva, due to posttranslational modifications, a pattern of 5-6 isozymes is observed. The isozymes are designated 1-6, in the order of increasing anodal mobility. As a result of the development of a rapid and sensitive electrophoresis system, with markedly higher resolution than previously reported, we concluded that a previously proposed model (Karn et al., Biochem. Genet. 1973, 10, 341-350) is inadequate to explain the origin of the various bands. We propose an alternative model that fits in with our new and previously made observations. According to this model, band 2 is the primary gene product and band 1 is its glycosylated counterpart--with only one neutral oligosaccharide present on each molecule. Band 3 originates from band 1 by the transialidase-catalyzed incorporation of sialic acid into the biantennary chain. Bands 4 and 6 originate from bands 2 and 4, respectively, by deamidation; band 5 is the deamidation product of amylase with an acidic oligosaccharide (band 3). Only a minor part of band 3 consists of the deamidation product of band 1. Peptide Asn-Gly-Ser (residues 427-429) is the most probable candidate for glycosylation; literature data suggests that deamidation occurs in the stretch Glu-Asn-Gly-Lys-Asp (residues 364-368) and Asn-Gly-Asn-Cys (residues 474-477). Both glycosylation and deamidation might play a role in the clearance of amylase from the systemic circulation. The electrophoresis system described is a powerful tool to determine amylase isozyme distributions in health and disease, especially for the screening of alterations seen in ectopically produced amylase.

Production of salivary type alpha-amylase in human lung cancer

alpha-Amylase, which is produced by lung cancer tissue, was studied by cloning cDNAs from a cell line originating from lung cancer that produces amylase. Sequencing studies with this cDNA showed that the expressing gene is of the salivary type. The specific location of the start point of transcription, as revealed by S1 mapping, supported this conclusion.

A novel type of human alpha-amylase produced in lung carcinoid tumor

A novel type of alpha-amylase was detected in a lung carcinoid tissue after surveying the cDNA library constructed from this tumor mRNA. Nucleotide sequence analysis showed that the amylase expressed in this carcinoid tumor has 13 and 6 amino acid substitutions when compared with salivary amylase (Amy1) and pancreatic amylase (Amy2), respectively. The nucleotide sequence homologies of cDNAs between this carcinoid amylase and amy1, amy2 are 97.5% and 98.2%, respectively. The nucleotide sequence comparison strongly suggests that this new amylase is the product of the amy3 gene that has been detected in human genome [Emi et al., Gene 62 (1988) 229-235]

Biochemistry of human alpha amylase isoenzymes

The purpose of this article is to review recent literature on the isoenzymes of alpha amylase. Although some studies are cited from the literature of fields other than clinical biochemistry, the aim is to bring together findings that may be of interest to clinical laboratory physicians and scientists. It is hoped that this will be useful in suggesting further studies of amylase. To this end, the review is more selective than exhaustive. The review will discuss the history and chemistry alpha amylases, the measurement of amylase and amylase isoenzymes, posttranslational modifications of human amylases, and the genetics of human pancreatic and salivary amylases. Finally, we will discuss other tissue sources of amylase with emphasis on "genital" amylases and their relationship to the amylase found in serous ovarian tumors.

Corrected sequences of cDNAs for human salivary and pancreatic alpha-amylases [corrected]

The nucleotide sequences of the cloned human salivary and pancreatic alpha-amylase cDNAs correspond to the continuous mRNA sequences of 1768 and 1566 nucleotides, respectively. These include all of the amino acid coding regions. Salivary cDNA contains 200 bp in the 5'-noncoding region and 32 in the 3'-noncoding region. Pancreatic cDNA contains 3 and 27 bp of 5'- and 3'-noncoding regions, respectively. The nucleotide sequence homology of the two cDNAs is 96% in the coding region, and the predicted amino acid sequences are 94% homologous. Comparison of the sequences of human alpha-amylase cDNAs with those previously obtained for mouse alpha-amylase genes (Hagenbuchle et al., 1980; Schibler et al., 1982) showed the possibility of gene conversion between the two genes of human alpha-amylase.

Study of the interaction between NADP-dependent dehydrogenase and immobilized adenosine 2'-monophosphate by means of affinity electrophoresis

A water-soluble 8-substituted adenosine 2'-monophosphate-polyacrylamide (8-sub-2'-AMP-PA) was prepared as a new affinity ligand for the determination of the dissociation constants of the interactions between immobilized 8-sub-2'-AMP and NADP-dependent dehydrogenases (NADP-dependent DH), NAD-dependent dehydrogenases (NAD-dependent DH) and phosphorylase by means of affinity electrophoresis. From the dissociation constants, it was found that NADP-dependent DH had a much stronger affinity to immobilized 8-sub-2'-AMP than did NAD-dependent DH and phosphorylase. On the other hand, NADP-dependent DH had a much weaker affinity to immobilized 8-sub-5'-AMP than did NAD-dependent DH. The effects of NADP+ and NAD+ on the interaction between immobilized 8-sub-2'-AMP and NADP-dependent DH were also investigated by means of affinity electrophoresis. NADP+ inhibited the interaction specifically, but NAD+ did not inhibit the interaction. These results indicate that 8-sub-2'-AMP binds to the coenzyme binding site of NADP-dependent DH, while other compounds, such as 8-sub-5'-AMP and NAD+, do not bind to NADP-depenndent DH. Such a difference suggests that the phosphate group at position 2' in 2'-AMP and NADP+ is important for the binding at the coenzyme binding site of NADP-dependent DH.

Amylase producing lung cancer. Electronmicroscopical and biochemical studies

A case of the lung cancer associated with marked elevation of serum (7820 IU/1) and of urinary amylase (2225 IU/1) was autopsied. Material was examined histopathologically, electronmicroscopically and biochemically. The pulmonary tumor tissues showed histological pattern of papillary adenocarcinoma. In addition to the small round bodies which were very similar to secretory granules, many large round bodies were noticed, diffusely distributed in the tumor cell. These large round bodies ranged from 0.2 to 0.7 micrometers in diameter and showed a lamellar or annular pattern. The soluble phase of the homogenized pulmonary tumor tissues had an amylase level of 11,300 IU/g of protein, which consisted of S-type isoamylase with minor components. Cholesterol, triglyceride and phospholipid were also present at greater concentration in the tumor tissue than the normal pulmonary tissue. The large round bodies appeared too, to be amylase including bodies from the electronmicroscopical and biochemical findings.

Study of the interaction between L-lactate dehydrogenase isoenzymes and immobilized 8-substituted adenosine 5'-monophosphate by means of affinity electrophoresis

A water-soluble 8-substituted adenosine 5'-monophosphate-polyacrylamide (8-sub-5'-AMP-PA) was prepared as an affinity ligand for the affinity electrophoresis of L-lactate dehydrogenase (LDH). According to the principles of affinity electrophoresis, the dissociation constants of the interaction between immobilized 8-sub-5'-AMP and rabbit LDH isoenzymes [LDH-1(H4), LDH-2(H3M), LDH-3(H2M2), LDH-4(HM3) and LDH-5(M4)], beef LDH-1(H4) and LDH-5(M4) and pig LDH-1(H4) were calculated. Both rabbit and beef LDH-5 (muscle-type isoenzymes) had approximately a 35-fold stronger affinity to immobilized 8-sub-5'-AMP than has their LDH-1 (heart-type isoenzymes). The effects of free nucleotides on the interaction between immobilized 8-sub-5'-AMP and LDH isoenzymes were also investigated by affinity electrophoresis. NAD+ has a stronger affinity to LDH-5(M4) than had 5'-AMP and 5'-IMP, while NMN, adenosine and fructose 6-phosphate had no affinity.

Ectopic production of salivary type amylase by a pseudomesotheliomatous carcinoma of the lung

A pseudomesotheliomatous carcinoma of the lung which appeared to be ectopically secreting large quantities of salivary (S) type amylase is described. This unusual variant of adenocarcinoma may mimic a mesothelioma, but is distinguished from mesothelioma by its histiological and histochemical features.

Ectopic production of a salivary type amylase by adenocarcinoma cells: demonstration by a culture technique

Characterization of an elevated amylase activity in ascitic fluid obtained from a patient with carcinomatous peritonitis is described; ninety-one percent of the increased amylase activity in the fluid was of salivary type and the remainder of pancreatic type, when studied by ion-exchange chromatography. Culture of ascitic cells successfully demonstrated morphologically characterized tumor cells surviving for at least 31 days. During that period, significant amylase activities were detected in the culture media, and the isozyme pattern was a single band whose electrophoretic mobility corresponded to salivary amylase. The data obtained indicate that the ascites amylase of salivary type was produced ectopically by the tumor cells.

The action of human pancreatic and salivary isoamylases on starch and glycogen

The hydrolytic properties of the isoenzymes of human pancreatic and salivary alpha-amylase (1,4-glucan 4-glucanohydrolase, EC 3.2.1.1) were studied. The eight pancreatic isoenzymes split glycogen and starch into glucose, maltose, maltotriose, maltotetraose and oligosaccharides of 5-10 glucose units. Maltotetraose is further digested to lower homologues. The percentage of conversion to those products is dependent on the substrate and varies from one isoenzyme to another. The six salivary isoenzymes split glycogen and starch into maltose, maltotriose, maltotetraose, pannose and oligosaccharides of 5--10 glucose units. Maltotetraose and pannose are further digested to lower homologues. The percentage of conversion to these products is dependent on the substrate and is specific for each isoenzyme.