PURIFICATION AND PROPERTIES OF TWO PECTATE LYASES PRODUCED BY ERWINIA CAROTOVORA

Abstract

Pectate lyase of Erwinia carotovora Er was separated into two active protein fractions, pectate lyases I (pI10.7) and II (pI10.1), by electro-focusing. These enzymes could be distinguished by SDS slab gel electrophoresis. Although they showed many similar properties, the optimal temperatures of pectate lyases I and II were 50° and 60°, respectively, and their K_m values were 0.12mg/ml and 1.1mg/ml. The amino acid composition was very similar in the two enzymes, but pectate lyase I contained a few more residues of lysine, valine, glycine and proline than pectate lyase II and fewer residues of isoleucine. The neutral sugar content of the lyases was 2.500 and 4.8%, respectively. From these results, pectate lyases I and II seem to be different enzyme proteins despite the fact that they have quite similar properties.