Amylase isoenzymes

Skude, 6. Electrophoretic separation, detection, and variation of amylase isoenzymes. Scand. J. Clin. Lab. Invest. (1975), 35, 41-47. 

Separation of human a-amylase isoenzymes by electrofo-cusing and their immunological properties. Clin. Chim. Acta (1975), 60, 207-213. 

L16. Lott, J. A., and Lu, C. J., Lipase isoforms and amylase isoenzymes Assays and application in the diagnosis of acute pancreatitis. Clin. Chem. 57, 66-68 (1991). 

P2. Panteghini, M., and Pagani, F., Time course of changes in serum activity of the P3 isoform of pancreatic amylase isoenzyme in patients with acute pancreatitis. Clin. Biochem. 22, 479—482... 

EI92 Chen, K., Shibata, Y. and Khayam-Bashi, H. (1985). Measurement of amylase isoenzymes and of their substrate preference by the use of an amylase inhibitor on the Ektachem 400, RA-1000 and Centrifichem. Clin. Chem. 31, 1002, Abstr. 522. 

Analytical Methods and Reference Intervals for Amylase Isoenzymes... 

Figure 2i-6 Cellulose acetate electrophoresis of amylase isoenzymes. M, Macroamylasemia P/S, mixture of two samples containing, respectively, pancreatic juice and saliva S, saliva.The anodal direction is downward.

Amylase isoenzymes are detected after separation over an isoelectric pH gradient. They then diffuse into an overlying, insoluble starch polymer containing a covalently bound dye. Release of the dye indicates where the isoenzymes are on the gel. Salivary and pancreatic amylases are secreted into blood as well as saliva and small intestine and each accounts for about half the amylase content of blood plasma. More recently, monoclonal antibodies specific for human salivary amylase have facilitated the measurement of amylases in serum during salivary gland malfunction, and facilitated the differentiation of salivary from pancreatic amylases (Fig. 12.13). 

Recio F, Villamil F. Charge selectivity and urine amylase isoenzymes. Kidney Int 1994 46 (SuppI 47) S89-S92. 

Storage of human saliva, serum, and duodenal secretion transformed the amylase fractions on cellulose acetate membrane electrophoresis into more-anionic forms. Incubation with lectins, proteases, D-glucosidases, neuraminidase, and some effectors did not modify this conversion, which was promoted by rising temperature and pH values. Increasing concentrations of ammonium ions delayed the transformation of amylolytic fractions, thus indicating non-enzymatic deamidation as the reason for amylase isoenzyme development. A change of molecular weight could be excluded. 

Separation of human amylase isoenzymes 274 Purification of cathepsin D from rat spleen 275... 

Purification of bull seminal plasma hyaluronidase Purification of ribonuclease B Purification of biliary glycoprotein I Separation of human amylase isoenzymes Purification of cathepsin D from rat spleen Purification of a cathepsin E-like acid proteinase from rat spleen... 

Human pancreatic juice, collected antiseptically and strictly free from other body fluids and juices, has been examined for the isoenzyme composition of a-amylase. Unlike those of the extract of and exudate from pancreatic tissue, the composition of a-amylase isoenzyme in the secreted juice was simple and consisted of only two isoenzymes, a major one and a minor one, and the reason for the difference in the isoenzyme composition was discussed. The major a-amylase isoenzyme was obtained in a crystalline state with a molecular weight of 5.4—5.5 x 10. ... 

Changes in the isoenzyme pattern of a-amylase have been shown to coincide with the beginning of the starch degradation period in the pods of field beans Vida faba). ° Mesophyll cells of the pods contained the same a-amylase isoenzymes as the endocarp, but exhibited a higher a-amylase activity that parallelled the much higher starch content of this tissue in comparison to the endocarp. Regulation of the starch breakdown was considered to be mediated in part by the formation of a special a-amylase isoenzyme. 

A study of the amylase isoenzymes during viral infection of the salivary glands and pancreas of mice has shown that Coxsackie B virus decreased the level of pancreatic amylase, whereas that of serum amylase increased. The level of amylase in the pancreas remained appreciably lower than normal for several months. Polyacrylamide gel electrophoresis of the serum-amylase isoenzymes indicated that hyperamylasemia was predominantly pancreatic in origin during the acute phase of infection the level of serum amylase subsequently returned to... 

A rapid method for determining the amylase isoenzymes in human sera and urine is based on separation of the isoenzymes by electrophoresis on a cellulose acetate membrane and visualization using a Blue Starch-agar plate. " The two isoenzymes which are separated possess the same characteristics as salivary and pancreatic amylases. The relative proportions of the isoenzymes are useful in distinguishing hyperamylasemias arising from disorders of the pancreas and parotid gland, etc. 

A solid-state radioimmunoassay has been developed for the detection and measurement of porcine pancreatic a-amylase. A double-antibody radioimmunoassay that is able to determine and detect small amounts of pancreatic amylase, even in the presence of amylase isoenzymes, has been reported. The assay was used to ascertain the effects of pancreatectomy on the levels of amylase in porcine tissues, and it was concluded that the pancreas contributes significantly to the levels of circulating amylase. 

Amylase isoenzymes in six varieties of oats Avena sativa) have been examined by agar gel electrophoresis. Three distinct zymograms were detected in aqueous extracts of the seedling endosperms, but no differences were detected among the varieties. The results indicate that amylase zymograms could be used to identify varieties of oats. 

Finnegan, D. J., and Hope, R. M., 1970, The role of sialic acid in the serum amylase isoenzyme pattern of the marsupial mouse Sminthopsis crassicaudata. Austr. J. Exp. Biol. Med. Sci. 48 237-240. 

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