Occurrence of three forms of glycogen phosphorylase and flight-induced enzyme activation in fat body of the american cockroach, Periplaneta americana

Abstract 1. 1. Ion exchange chromatography of fat body glycogen phosphorylase of Periplaneta americana yielded three activity peaks, identified as phosphorylases b, ab and a , with - AMP/+AMP activity ratio's of 0, 10 and 49%, respectively. 2. 2. In cockroaches at rest, phosphorylase occurred largely in the inactive b form, while both flight and corpus cardiacum extract caused a strong increase in the relative proportions of the active a and intermediate ab forms. 3. 3. After a post-flight resting period of 1 hr, phosphorylase activity in Periplaneta was still high, while in Locusta migratoria the enzyme activity had returned to the pre-flight resting level. 4. 4. Results are discussed in relation to the regulation of substrate mobilization for flight.