This step is the enzymatic transfer of a phosphate group from 1,3-bisphosphoglycerate to ADP by phosphoglycerate kinase , forming ATP and 3-phosphoglycerate . At this step, glycolysis has reached the break-even point: 2 molecules of ATP were consumed, and 2 new molecules have now been synthesized. This step, one of the two substrate-level phosphorylation steps, requires ADP; thus, when the cell has plenty of ATP (and little ADP), this reaction does not occur. Because ATP decays relatively quickly when it is not metabolized, this is an important regulatory point in the glycolytic pathway.
Glycolysis is the anaerobic catabolism of glucose. In other words, as its name implies, the pathway uses several enzyme catalyzed reactions to split (lysis) a sugar (glyco). Glycolysis occus in the cytosol. The Individual Reactions of Glycolysis The pathway of glycolysis can be seen as consisting of 2 separate phases. The first is the chemical priming phase requiring energy in the form of ATP, and the second is considered the energy-yielding phase. In the first phase, 2 equivalents of ATP are used to convert glucose to fructose 1,6-bisphosphate (F1,6BP). In the second phase F1,6BP is degraded to pyruvate, with the production of 4 equivalents of ATP and 2 equivalents of NADH. GLYCOLOSYS YIELDS: 8 ATP; 2NADH + H + , 4 ATP, -2 ATP