GLYCOGEN SYNTHETASE AND PHOSPHORYLASE IN RED AND WHITE MUSCLE OF RAT AND RHESUS MONKEY

Abstract

Homogenates of red and white muscles from rats and monkeys were assayed for total phosphorylase and phosphorylase a and for the total and independent forms of glycogen synthetase. Total and phosphorylase a activities were higher in the supernatant fraction of homogenates of white as compared with red muscle from both rats and monkeys. Both forms of phosphorylase were higher in white muscle from rats when assayed on whole homogenates. The total and d form of glycogen synthetase activities were higher in red muscle from both species of animals. The ratio of I/total synthetase was 2- to 3-fold higher in muscle from monkeys as compared with that from rats. These results support histochemical evidence that phosphorylase is higher in white muscle fibers and glycogen synthetase is higher in red muscle fibers.