PURIFICATION AND CHARACTERIZATION OF A PHYTASE FROM KLEBSIELLA-TERRIGENA

A cytoplasmatic phytase was purified about 410-foId to apparent homoge neity with a recovery of 28%. The enzyme is induceable under carbon li mitation in the presence of phytate. It behaves as a monomeric protein of a molecular mass of about 40 kDa. The phytase is rather specific f or phytate and exhibits optimal conditions for phytate degradation at pH 5.0 and 58 degrees C. Kinetic parameters for the hydrolysis of Na p hytate are K-M 300 mu M and K-cat 180 s(-1) at 35 degrees C and pH 5.0 . Phytate is hydrolyzed in a stepwise manner; the penta- and tetrakisp hosphate were identified as I(1,2,4,5,6)P-5 and I(1,2,5,6)P-4. Consequ ently, this enzyme is a 3-phytase (EC 3.1.3.8). (C) 1997 Academic Pres s.