This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
Which of the following enzyme is a constituent of HMP shunt- 
Select and explain. 
A. Glucose-6-phosphatase, B. Hexokinase, C. G-6-P dehydrogenase, D. Phosphorylase
C: G-6-P dehydrogenase
Answer: C: G-6-P dehydrogenase 
Explanation: Ans:C : G-6-P- dehydrogenase.The Hexose MonoPhosphate ShuntIt is also known as "Pentose phosphate Pathway" (PPP). This is alternative Glucose oxidation pathway. * Location: Cytoplasm of cells of the liver, adrenal coex, and lactating mammary glands.* Substrate: Glucose-6-phosphate.* Oxidative poion: Irreversible. Generates two NADPH, which can then be used in fatty acid synthesis and cholesterol synthesis and for maintaining reduced glutathione inside RBCs.* Nonoxidative poion: Reversible. Generates intermediate molecules (ribose-5-phosphate; glyceraldehyde-3-phosphate; fructose-6-phosphate) for nucleotide synthesis and glycolysis.* Regulation: Key enzyme in the pentose-phosphate pathway is glucose-6-phosphate dehydrogenase. Levels of glucose-6-phosphate dehydrogenase are increased in the liver and adipose tissue when large amounts ofcarbohydrates are consumed. Glucose-6-phosphate dehydrogenase is stimulated by NADP+ and inhibited by NADPH and by palmitoyl-CoA (pa of the fatty acid synthesis pathway).* Purpose: Functions as an alternative route for glucose oxidation that does not directly consume or produce ATP.