Allosteric inhibitor of pyruvate dehydrogenase
In the complete degradation of pyruvate, pyruvate dehydrogenase (PDH) and the citric acid cycle perform the oxidation of all substrate carbon to CO2. The hydrogen is retained in reduced form; it is subsequently oxidized in the respiratory chain Pyruvate is produced by glycolysis in the cytosol, while PDH and all subsequent degradative steps are located in the mitochondria. Therefore, pyruvate needs to be transpoed from the cytosol to the mitochondrial matrix. The outer mitochondrial membrane contains porins, which are membrane proteins that form non-specific pores and allow free permeation of most small metabolites, including pyruvate. In contrast, the inner mitochondrial membrane is much more restrictive, and it is permeable to only those metabolites for which it contains specific carrier systems. The pyruvate carrier is an active transpoer that co-transpos pyruvate and a proton. Red blood cells and blood platelets lack mitochondria and accordingly cannot degrade pyruvate. These cells reduce pyruvate to lactate, which they then release into the bloodstream
AMP
Acetyl CoA
ADP
Citrate
Enzymes