Although glycolysis and the pentose phosphate pathway have several common metabolites, they are markedly different otherwise. All of the following statements are true, EXCEPT:
Correct Answer: Thiamine is used as a coenzyme in both glycolysis and the pentose phosphate pathway
Description: The two major pathways of catabolism of glucose, glycolysis and the pentose phosphate pathway, having several common metabolites (as for example, glucose 6-phosphate and glyceraldehyde 3-phosphate) markedly differ in many other features.CO2 is produced in the pentose phosphate pathway but not in glycolysis; Mg2+ ions are required for both glycolysis (for the phosphorylation of glucose by glucokinase) and the pentose phosphate pathway (for the functioning of transketolase and several other enzymes). Thiamine is used only in the pentose phosphate pathway (in the form of thiamine pyrophosphate as the coenzyme of transketolase). Thiamine-dependent enzymes are not involved in glycolysis taking pa on later stages when pyruvate is either conveed to acetyl CoA by pyruvate dehydrogenase or (in microorganisms) is reduced to ethanol by pyruvate decarboxylase. Ref: Bender D.A., Mayes P.A. (2011). Chapter 21. The Pentose Phosphate Pathway & Other Pathways of Hexose Metabolism. In D.A. Bender, K.M. Botham, P.A. Weil, P.J. Kennelly, R.K. Murray, V.W. Rodwell (Eds), Harper's Illustrated Biochemistry, 29e.
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