Phosphorylase b kinase catalyzes the phosphorylation of serine in certain substrates, including troponin I. The alpha chain may bind calmodulin (By similarity). By phosphorylation of various serine residues and by calcium. Glycan biosynthesis; glycogen metabolism. Polymer of 16 chains, four each of alpha, beta, gamma, and delta. Alpha and beta are regulatory chains, gamma is the catalytic chain, and delta is calmodulin (By similarity). Although the final Cys may be farnesylated, the terminal tripeptide is probably not removed, and the C-terminus is not methylated. Belongs to the phosphorylase b kinase regulatory chain family.