Question

What reaction is represented in the diagram?

(a) Purine degradation pathway

(b) Oxidative step of pentose phosphate pathway

(c) Glycolysis

(d) TCA cycle

This question was posed to me in an international level competition.

This is a very interesting question from Clinical Significance of Angiotensin Converting Enzyme and Glucose-6-phosphate Dehydrogenase topic in section Clinical Enzymology of Enzyme Technology

Answer 1

Right option is (b) Oxidative step of pentose phosphate pathway

Explanation: Pentose phosphate pathway has two steps: oxidative and non-oxidative. Oxidative step is represented in the following diagram. Glucose-6-phosphate is converted to 6-phosphoglucono-δ-lactone by glucose-6-phosphate dehydrogenase. This is converted to 6-phosphogluconate which is then converted to ribulose-5-phosphate by 6-phosphogluconate dehydrogenase. This is called oxidative decarboxylation.