Glycolysis

 Oxidation of glucose to pyruvate is called glycolysis. It was first described by Embden-Meyerhof and Parnas. Therefore it is also called as Embden-Meyerhof pathway. Glycolysis occurs virtually in all cells of tissues. Erythrocytes and nervous

tissues derive the energy chiefly from glycolysis. This pathway is unique in the sense that it can proceed in both aerobic  or in presence of O2 and anaerobic in the absence of O2 conditions. All the enzymes of glycolysis are found in the extra mitochondrial soluble fraction of the cell, the cytosol or cytoplasm .

Reactions of glycolytic pathway

Sequence of reactions of glycolytic pathway which degrades glucose to pyruvate are represented below. The sequence of reactions taking place in glycolysis is explained below.

 

During glycolysis NAD+ is reduced to NADH. At the same time, glyceraldehyde 3-phosphate is oxidized to 1,3-bisphosphoglycerate. To conserve the coenzyme NAD+, NADH must be reoxidized. Under anaerobic conditions this is done when pyruvic acid is converted to lactic acid. In the presence of oxygen, NADH, can be oxidized to NAD+ with the help of the respiratory enzymes.