Purification and Characterization of a Phytase fromKlebsiella terrigena

A cytoplasmatic phytase was purified about 410-fold to apparent homogeneity with a recovery of 28%. The enzyme is induceable under carbon limitation in the presence of phytate. It behaves as a monomeric protein of a molecular mass of about 40 kDa. The phytase is rather specific for phytate and exhibits optimal conditions for phytate degradation at pH 5.0 and 58°C. Kinetic parameters for the hydrolysis of Na phytate areKM300 μm andkcat180 s−1at 35°C and pH 5.0. Phytate is hydrolyzed in a stepwise manner; the penta- and tetrakisphosphate were identified as I(1,2,4,5,6)P5and I(1,2,5,6)P4. Consequently, this enzyme is a 3-phytase (EC 3.1.3.8).