Phosphorylase kinase, alpha 1
Phosphorylase b kinase regulatory subunit alpha, skeletal muscle isoform is an enzyme that in humans is encoded by the PHKA1 gene. It is the muscle isoform of Phosphorylase kinase.
The PHKA1 gene encodes the alpha subunit of muscle phosphorylase kinase, a key regulatory enzyme of glycogen metabolism. Phosphorylase kinase consists of 4 copies of an alpha-beta-gamma-delta tetramer. The alpha, beta, and gamma subunits have several isoforms; the delta subunit is calmodulin. PHKA2 encodes the alpha subunit of liver-specific phosphorylase kinase and is also located on the X chromosome.
A deficiency of this enzyme causes glycogen storage disease type IXd.
