alpha-Amylase assay: current state and future development.

Abstract

alpha-Amylase can be measured continuously with the aid of 4-nitrophenyl glucosides, especially 4-nitrophenyl maltotrioside; the large scale enzymatic synthesis of this compound seems to be possible. Another method, which does not suffer from interference by endogenous glucose, consists of the hydrolysis of maltotetraose by alpha-amylase, followed by the determination of maltose. The substrate and the auxiliary enzymes are, however, relatively expensive. Continous methods, based on the measurement of the glucose released by alpha-amylase, are more sensitive. However, they suffer from interference by blood sugar, with exception of mechanized procedures, which remove glucose by gel filtration of the sample. Moreover these methods need alpha-glucosidase, which degrades maltooligosaccharides consisting of less than seven glucose units, whereas higher polymerized substrates show slower degradation rates by amylase, and the kinetics are not easy to understand.