African Journal of Biotechnology Vol. 2 (12), pp. 645-648, December 2003

ISSN 1684-5315  © 2003 Academic Journals

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An overview of the microbial α-amylase family

N. S. Reddy*, Annapoorna Nimmagadda and K. R. S. Sambasiva Rao

Centre for Biotechnology, Nagarjuna University, Nagarjuna Nagar -522 510, A.P., India.

*Corresponding author. E-mail: naru_sri@yahoo.com.

Accepted 21 November 2003  

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 (b/a)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.