Structural and Catalytic Properties of Lobster Muscle Glycogen Phosphorylase

Structural and catalytic properties of lobster muscle glycogen phosphorylase.

McArdle's disease-muscle glycogen phosphorylase deficiency.

The conversion of lobster muscle phosphorylase a to b and phosphorylase b to a.

Lobster muscle phosphorylsse, in common with the phosphorylases of many other animal species, occurs in forms with different requirements for activity (1). Phosphorylase a is an active form; whereas phosphorylase 6 is active only in the presence of adenylic acid (AMP). It has been demonstrated with enzymes from mammalian species that phosphorylase may be converted from one form to another by re...

Fluorescence of glycogen phosphorylase b. Structural transitions and energy transfer.

The fluorescence properties of glycogen phosphorylase b and its apoenzyme are described. At neutral pH the enzyme has two fluorescence bands: one caused by the protein moiety (maximum at 335 nm, quantum yield 0.12) and the other associated with the cofactor, pyridoxal 5’-phosphate (maximum at 535 nm, quantum yield 0.012). Pyridoxal5’-phosphate can be regarded as a native reporter group of phosp...

Rabbit skeletal muscle phosphorylase kinase. Comparison of glycogen synthase and phosphorylase as substrates.

The Ca”-stimulated phosphorylation of rabbit muscle glycogen synthase (EC 2.4.1.11) catalyzed by phosphorylase kinase (EC 2.7.1.38) was characterized and compared with the reaction involving phosphorylase (EC 2.4.1.1). By comparing reaction rates at equal concentrations (on a mass basis), the activity ratio of phosphorylase/synthase varied from 30 (0.05 mg/ml) to approximately 8 (1 mg/ml). A ba...