Functional Expression of Amylosucrase, a Glucan-Synthesizing Enzyme, from Arthrobacter chlorophenolicus A6

A gene (acas) designated as alpha-amylase was cloned from Arthrobacter chlorophenolicus A6. The multiple amino acid sequence analysis and functional expression of acas revealed that this gene really encoded an amylosucrase (ASase) instead of alpha-amylase. In fact, the recombinant enzyme exhibited typical ASase activity by showing both sucrose hydrolysis and glucosyltransferase activities. The purified enzyme has a molecular mass of 72 kDa and exhibits optimal hydrolysis activity at 45 degrees C and a pH of 8.0. The analysis of the oligomeric state of ACAS with gel permeation chromatography revealed that the ACAS existed as a monomer.