Characterisation of a thermostable α‐amylase from Bacillus brevis

Abstract

Biochemical characterization of a novel heat‐stable α‐amylase, produced by a thermophilic strain of Bacillus brevis, has been made. The pattern of the enzyme action on different substrates was studied. It was found that reducing groups were rapidly liberated from amylopectin, soluble and insoluble starch compared to amylose and glycogen. B. brevisα‐amylase acted via endo‐attack producing mainly maltopentaose during the first hour of hydrolysis. The enzyme showed high activity towards maltohexaose and maltoheptaose. The α‐amylase from B. brevis had a neutral pI and was found to be a glycoprotein, containing 9.2% (by mass) neutral sugars. The enzyme protein possessed a unique high glycine content. Calcium or sodium ions in appropriate concentrations were required for enzyme thermostability. Copyright © 1992, Wiley Blackwell. All rights reserved