Question

In the glycolytic pathway, the enzyme triose phosphate isomerase catalyzes the production of glyceraldehyde 3-phosphate (GAP) from dihydroxyacetone phosphate (DHAP). GAP continues through glycolysis via the reaction catalyzed by glyceraldehyde 3-phosphate dehydrogenase. In a muscle (myocyte) cell culture model, anaerobic conditions lead to cell death when triose phosphate isomerase is inhibited. In this same model, cells with inhibited triose phosphate isomerase survive under aerobic conditions. Briefly explain these findings including a discussion of energy production in anaerobic versus aerobic metabolism.

Answer 1

In an anaerobic environment, organisms convert glucose into ethanol or lactate. In this condition, glycolysis generates 2 molecules of ATP and one molecule of NADH with the pyruvate. NADH molecule supports glycolysis by oxidized to NAD+ during the fermentation process.

Here one 6-C molecule breaks into two molecules G3P and DHAP, TPI or triose phosphate isomerase interconvert these two isomers and each triose is responsible for the production of two ATP molecules but if TPI is inhibited then there will be one ATP production which is not enough for supporting cellular process under the absence of oxygen and cell do not survive.

But in aerobic conditions pyruvate converted to acetyl CoA which produces 3 NADH, 1 FADH2, and 1 ATP that will get enough ATP by the oxidative phosphorylation hence will survive even if TPI is inhibited.