An overview of the microbial -amylase family

Abstract

Amylases are enzymes which hydrolyze the starch molecules into polymers composed of glucose units. α-Amylases are ubiquitous in distribution, with plants, bacteria and fungi being the predominant sources. Most of the microbial α-amylases belong to the family 13 glycosyl hydrolases, and they share several common properties. But different reaction specificities have been observed across the family members. Structurally α-amylases possess (β/α)8 or TIM barrel structures and are responsible for hydrolysis or formation of glycosidic bonds in the a-conformation. Stability of the α-amylases has been widely studied; pH and temperature have very important roles to play. Engineering the enzymes for improved stability enhances their use industrially. This review focuses on the distribution, structural-functional aspects and factors for enhancing the stability of α-amylases. Key words : α-Amylase, TIM barrel, glycosylhydrolases. African Journal of Biotechnology Vol. 2 (12), pp. 645-648, December 2003