Chapter 16, Problem 33P

Summary Introduction

To explain: The reason why two steps of pyruvate oxidative decarboxylation, do not involves any of the three carbons of pyruvate, but are necessary for the operation of PDH complex.

Introduction: Pyruvate is obtained from glycolysis and then transported into matrix of mitochondria through mitochondrial pyruvate carrier. In mitochondrial matrix, an enzyme called pyruvate dehydrogenase complex (PDH) converts the pyruvate into acetyl-CoA.

Three types of enzyme are involved in the composition of PDH. These enzymes are ${\text{E}}_{\text{1}}$ (pyruvate dehydrogenase), ${\text{E}}_2$ (dihydrolipoyl transacetylase), and ${\text{E}}_3$ (dihydrolipoyl dehydrogenase). These enzymes are found in mitochondria of eukaryotes and cytosol of bacteria.