Phosphorylase Kinase (PhK)

Phosphorylase kinase (PhK) is a large, multi-subunit serine/threonine-specific protein kinase that plays a central role in glycogen metabolism. Its primary function is to activate glycogen phosphorylase by phosphorylation, thereby promoting the breakdown of glycogen into glucose-1-phosphate. The holoenzyme has a complex quaternary structure composed of four types of subunits: α (alpha), β (beta), γ (gamma; catalytic subunit), and δ (delta; regulatory/calmodulin subunit). PhK activity is tightly regulated through multiple mechanisms, including allosteric regulation by calcium ions and reversible phosphorylation by protein kinase A (PKA).

Not applicable, direct inhibitors currently unknown