OSTRICH PANCREATIC ALPHA-AMYLASE - KINETIC-PROPERTIES, AMINO-TERMINALSEQUENCE AND SUBSITE STRUCTURE

Ostrich pancreatic alpha-amylase (OPA) was purified to homogeneity in the presence of protease inhibitors by a single-step affinity chromato graphy technique. The first 53 amino acids of the N-terminus were iden tified by gas-phase sequencing. From kinetic parameters (k(cat)/K-m) a subsite profile was established leading to a five subsite model for O PA. The pK(a) values of catalytic residues were determined as 5.75 and 8.36. Inhibition of OPA by monosaccharides, beta-cyclodextrin and a w heat alpha-amylase inhibitor was studied.