Purification, Characterization, and Biochemical Properties of α-Amylase from Potato

Purification, characterization and biochemical properties of α-amylase from post harvest Bangladeshi Potato (Solanum tuberosum L.) were investigated. The α-amylase was purified by successive chromatography on DEAE and CM-cellulose columns with a yield of 24.24%. SDS-PAGE showed a molecular weight of 44 kDa for the enzyme that contain 2.8% sugar. The enzyme lost total activity in the presence of the chelating agent EDTA, confirming it was an α-type amylase. The enzyme displayed optimum activity at pH 7.2 and 37℃, with an apparent Km value of 0.26% using starch as its substrate. The enzyme was strongly inhibited by Cu²+, Fe²+ and Zn²+; moderately by Li+, Hg+ and Cd²+; and slightly by Ag+, K+, Mn²+ and Mg²+. Conversely, Fe³+ and Na+ appreciably enhanced activity, while adding calcium ion nearly doubled enzyme activity. In addition, the activity of α-amylase gradually decreased with increasing concentrations of urea. Thus, potato α-amylase is an attractive target for study to better understand the structure-function relationships of α-amylases.