NAD+ linked dehydrogenase is

Pyruvate Dehydrogenase Complex - Inside the mitochondria, pyruvate is oxidatively decarboxylated to acetyl CoA by pyruvate dehydrogenase (PDH). It is a multi-enzyme complex with 5 co-enzymes and 3 apo-enzymes. The coenzymes needed are: Thiamine pyrophosphate (TPP) Co-enzyme A (CoA) FAD NAD+ Lipoamide. The lipoic acid, otherwise called thioctic acid has two sulphur atoms and 8 carbon atoms. It can accept or donate hydrogen atoms. 6. The enzyme pa of the PDH complex is made up of three component enzymes. 6-A. Pyruvate Dehydrogenase (Enzyme 1): It catalyses oxidative decarboxylation. TPP is required in this step. So, Thiamine, a B-complex group vitamin is essential for utilization of pyruvate.An enzyme bound hydroxylethyl TPP is formed. 6-B. Dihydro Lipoyl Trans Acetylase (Enzyme 2): Then, hydroxyethyl group is oxidized to form an acetyl group and then transferred from TPP to lipoamide to form acetyl lipoamide. 6-C. Dihydro Lipoyl Dehydrogenase (Enzyme 3): The last step is the oxidation of lipoamide. At the end of the reaction the cofactors, namely TPP, Lipoamide and FAD are regenerated. REF: DM VASUDEVAN TEXTBOOK OF BIOCHEMISTRY,EIGHTH EDITION,PG.NO.,135.