Erythroblasts isolated from a bone marrow biopsy sample of a patient with neonatal jaundice are incubated in a medium containing radiolabeled glucose. The cells are unable to generate NADPH from glucose metabolism but are able to convert fructose-6-phosphate to ribose-5-phosphate, which is required for nucleic acid synthesis. Which of the following enzymes is essential for the latter conversion?

Question

Erythroblasts isolated from a bone marrow biopsy sample of a patient with neonatal jaundice are incubated in a medium containing radiolabeled glucose.  The cells are unable to generate NADPH from glucose metabolism but are able to convert fructose-6-phosphate to ribose-5-phosphate, which is required for nucleic acid synthesis.  Which of the following enzymes is essential for the latter conversion?

Quizplus · Accepted Answer

Eductional Objective: The pentose phosphate pathway consists of an oxidative (irreversible) branch and a nonoxidative (reversible) branch, and each can function independently based on cellular requirements.  Transketolase, an enzyme of the nonoxidative branch, is responsible in part for the interconversion of ribose-5-phosphate (nucleotide precursor) and fructose-6-phosphate (glycolytic intermediate).

Erythroblasts Isolated from a Bone Marrow Biopsy Sample of a Patient