Description
Requires Ca2+ and calmodulin for activity. The enzyme phosphorylates a specific serine residue in each of the subunits of the dimeric phosphorylase b. For muscle phosphorylase but not liver phosphorylase, this is accompaniedby a further dimerization to form a tetrameric phosphorylase. The enzyme couples muscle contraction with energy production via glycogenolysis-glycolysis by catalysing the Ca2+-dependent phosphorylation and activation of glycogen phosphorylase b. The γ subunit of the tetramericenzyme is the catalytic subunit