BIOCHEMICAL-PROPERTIES OF AMYLASE ISOZYMES FROM GAMMARUS-PALUSTRIS - A COMPARATIVE-STUDY

Two major alpha-amylase isozymes from Gammarus palustris were purified and characterized. These isozymes, Amy I-W and Amy I-c, exhibit a sea sonal pattern of expression, In this article we investigate whether th e seasonal variation has an adaptive significance, In addition, the sp ecies-specific properties of amylases were studied, Purification of th e isozymes was achieved by sequential glycogen-ethanol precipitation, Sephadex G-200 and ion exchange chromatography. Characterization in te rms of K-m, activity patterns at different temperatures, pH values and salt concentrations was done for both isozymes, In addition, the dist ribution of enzymatic products was analyzed in a high-performance liqu id chromatography system, In all conditions tested, the two isozymes g ave similar results, This observation suggests that the seasonal chang e in amylase expression pattern does not result in enzymes differentia lly suited for seasonal variation in conditions, A comparative analysi s showed that G. palustris amylases are apparently distinct from other amylases, These distinctions were seen as an unusually low K-m value, an activity peak at low NaCl concentration, a relatively high pH opti mum and the predominant formation of maltotriose.