Pyruvate dehydrogenase is inhibited allosterically by

Regulation of PDH: PDH is subject to regulation by allosteric mechanisms and covalent modification. Allosteric inhibitors are the products acetyl CoA and NADH. PDH or E1 is covalently modified by phosphorylation by PDH kinase and dephosphorylated by PDH phosphatase. The dephosphorylated form of the enzyme is active. Hence, activators of PDH kinase like ATP, NADH and acetyl CoA inhibit PDH reaction. PDH phosphatase is activated by Ca++, Mg++ and AMP; this will increase the rate of PDH reaction where as PDH kinase is inhibited by Ca++. When there is adequate ATP and acetyl CoA, the enzyme is inhibited. Ref: DM VASUDEVAN TEXTBOOK OF BIOCHEMISTRY, SIXTH EDITION,PG.NO.,101.