Abstract
In order to obtain further information on the regulation of the glycogen-degradating meta-holism in fish skeletal muscle, the activation by calcium ion and other substances, autocatatytic reaction and limited proteolysis of carp muscle phosphorylase kinase (EC.2.7.1.38) were studied.
It was shown that the activation pattern of the carp enzyme by calcium ion and calmodulin was the same as that of rabbit enzyme, suggesting the presence of calcium regulation mechanism in the fish muscle.
The activation by glycogen of the fish enzyme was very low; and also the extent of activation by the procedures of auto-catalytic reaction and limited proteolysis of the fish enzyme were less than that of rabbit enzyme. That the fish enzyme obtained by the limited proteolysis with trypsin lost the response to calcium sensibility and γ-subunit of the enzyme was susceptible to the limited proteolysis, differed from that of rabbit enzyme.
