One step purification and characterization of an extracellular α-amylase from marine Vibrio sp.

An alpha-amylase was purified from marine Vibrio sp. using starch affinity method with molecular mass of 52.480 kDa. This amylase showed maximum activity at 55-60degreesC and pH 6.5 and retain 85% of maximal activity after 30 min preincubation at 65 degreesC. The enzyme was inhibited by ethylenediaminetetra-acetate (EDTA) and [ethylenebis(oxonitrilo)]tetra-acetate (EGTA) while divalent metal ions, such as Fe2+, Mn2+, Co2+. Ca2+, Mg2+ and Cu2+ could restored near 25-55% of maximal activity suggesting that the metal ions need for the enzyme activity. Digestion of corn-starch by the enzyme showed random cleavage with various sizes of products, indicating endo action of the enzyme. Chemical modification suggested involvement of Lys, Trp, Asp/Glu and His in the enzyme activity. The starch affinity method used here showed high yield purified amylase with very low experimental cost. (C) 2004 Elsevier Inc. All rights reserved.