[Isoenzymes of phosphorylase from skeletal muscles of cyclostomata and raw-boned fish].

Separation and partial purification of isoenzymes of phosphorylase B from skeletal muscles of lamprey (Lampetra) and carp (Cyprinus carpio) was carried out. Isoenzyme I was adsorbed on DEAE cellulose and eluted by KCl; isoenzyme II was not adsorbed on DEAE cellulose. A number of kinetic characteristics of phosphorylase of the coldblooded were determined, e. g. Km values for glucose-1-phosphate, glycogen and AMP; Ki for glucose-6-phosphate; stability towards denaturation (heating and effect of urea) and pH optimum. It was observed that in the course of evolution of vertebrates the Km values for substrates and allosteric activator (AMP), as well as the inhibition by glucose-6-phosphate showed a decrease. Isoenzymes I and II of phosphorylase B were found non-identical with respect to some molecular characteristics, in carp the differences being far more pronounced than in lamprey.