PDK2 [SEP] found in taxon
inactive conformation.
Function.
The Pyruvate Dehydrogenase (PDH) complex must be tightly regulated due to its central role in general metabolism. Within the complex, there are three serine residues on the E1 component that are sites for phosphorylation; this phosphorylation inactivates the complex. In humans, there have been four isozymes of Pyruvate Dehydrogenase Kinase that have been shown to phosphorylate these three sites: PDK1, PDK2, PDK3, and PDK4. PDK2 has been identified as the most abundant isoform in human tissues. Through many studies,
tissue specific. PDK1 is ample in heart cells. PDK3 is most abundant in testis. PDK2 is present in most tissues but low in spleen and lung cells. PDK4 is predominantly found in skeletal muscle and heart tissues.
Mechanism.
Pyruvate dehydrogenase is deactivated when phosphorylated by PDK. Normally, the active site of pyruvate dehydrogenase is in a stabilized and ordered conformation supported by a network of hydrogen bonds. However, phosphorylation by PDK at site 1 causes steric clashes with another nearby serine residue due to both the increased size