Cloning, sequencing, characterization, and expression of a new alpha-amylase isozyme gene (amy3) from Pseudomonas sp.

A new gene encoding an alpha -amylase has been cloned, sequenced and expres sed in E. coli from an alkaliphilic Pseudomonas sp. KFCC10818. The structur al gene is 1356 base pairs long and encodes a protein of 452 amino acids. T he recombinant alpha -amylase has been purified and biochemically character ized. Molecular mass of the protein deduced from SDS-PAGE was 50 kDa. The e nzyme showed an activity optimum at pH 8 and at 40 degreesC with complete s tability at pH 13 for 3 h. The enzyme released maltose and maltotriose on h ydrolysis of soluble starch. Amylose was hydrolysed over 5 times faster tha n amylopectin by the enzyme while the hydrolysis of cyclodextrin or pullula n was negligible.