glycolytic

Glycolytic is an adjective relating to glycolysis, the principal cytosolic pathway of glucose metabolism that converts glucose into pyruvate with the production of ATP and NADH. It occurs in the cytoplasm of nearly all organisms and tissues, functioning under both anaerobic and aerobic conditions. In the standard pathway, one molecule of glucose is converted to two molecules of pyruvate, yielding a net gain of two ATP and two NADH per glucose.

The pathway consists of two phases: an energy investment phase that consumes ATP to phosphorylate glucose and its derivatives, and an energy payoff phase that generates ATP and NADH through substrate-level phosphorylation and oxidation. Key enzymes include hexokinase or glucokinase; phosphofructokinase-1, a major rate-limiting control point; aldolase; glyceraldehyde-3-phosphate dehydrogenase; and pyruvate kinase.

The fate of pyruvate depends on oxygen availability and cellular context. In aerobic conditions, pyruvate can enter mitochondria for further oxidation via the pyruvate dehydrogenase complex and the citric acid cycle; under anaerobic conditions, it is reduced to lactate in some tissues, regenerating NAD+ for glycolysis. In many rapidly proliferating cells, including cancer cells, glycolysis is upregulated, a phenomenon known as the Warburg effect, and lactate production can be prominent even with sufficient oxygen.

As an overarching term, glycolytic describes anything pertaining to or derived from glycolysis, including glycolytic enzymes, intermediates, and regulatory mechanisms. The term is commonly used in biochemistry, physiology, and pathology to contrast with oxidative or gluconeogenic processes.