Crystallization and Reaction Mechanism of Yeast Phosphoglucomutase

Publisher Website
Google Scholar
Abstract
A procedure for crystallization of phosphoglucomutase (EC 2. 7. 5. 1) from baker'syeast is presented. The purified enzyme preparation was homogeneous as judged from ultracentrifugation and electrophoresis. Yeast phosphoglucomutase was not influenced by the addition of Mg2+ and was-strongly inhibited by chelating-agents. However, the enzyme was stimulated about 1.7-fold by simultaneous addition of Mg2+ and chelating-agents without preincubation. The reaction mechanism of the yeast enzyme was studied. It was concluded by kinetic experiments that the enzyme-substrate-coenzyme ternary complex is the active intermediate in yeast phosphoglucomutase reaction. It was suggested in the pattern of Lineweaver-Burk plots that the reaction mechanism in yeast phosphoglucomutase fitted Cleland's “random sequential” pathway and substrate binding to the enzyme decreased the affinity of coenzyme to the enzyme, and vice versa. This mechanism was able to interpret also the phenomena in the rabbit muscle enzyme supporting “ping-pong” pathway.

This publication has 0 references indexed in Scilit: