Alternate Fates of Pyruvate

Pyruvate can be metabolized to products other than lactate.
A. Oxidative decarboxylation to acetyl CoA
Oxidative decarboxylation of pyruvate by the PDHC is an important pathway in tissues with a high oxidative capacity such as cardiac muscle (Fig. 1). PDHC irreversibly converts pyruvate, the end product of aerobic glycolysis, into acetyl CoA, a TCA cycle substrate  and the carbon source for fatty acid synthesis .

Figure 8.24 Summary of the metabolic fates of pyruvate. TPP = thiamine pyrophosphate. TCA = tricarboxylic acid; NAD(H) = nicotinamide adenine dinucleotide; CoA = coenzyme A; CO2 = carbon dioxide.
B. Carboxylation to oxaloacetate
Carboxylation of pyruvate to oxaloacetate by pyruvate carboxylase is a biotin-dependent reaction (see Fig. 1). This irreversible reaction is important because it replenishes the TCA cycle intermediate and provides substrate for gluconeogenesis .
C. Reduction to ethanol (microorganisms)
The reduction of pyruvate to ethanol occurs by the two reactions summarized in Figure 1. The decarboxylation of pyruvate to acetaldehyde by thiamine-requiring pyruvate decarboxylase occurs in yeast and certain other microorganisms but not in humans.

مواضيع ذات صلة

Blood clotting (coagulation)

Platelet Plug Formation: Aggregation

Platelet Plug Formation: Activation

Platelet Plug Formation: Adhesion

Limiting Clotting : Fibrinolysis

Limiting Clotting : Inactivating proteins

Fibrin Meshwork Formation : Pathways

Fibrin Meshwork Formation : Formation of γ-carboxyglutamate residues

Fibrin Meshwork Formation :Role of phosphatidylserine and calcium

Fibrin Meshwork Formation: Proteolytic cascade

Blood Clotting : Overview

Biotechnology and Human Disease