Vitamin hexose monophosphate

Thiamine pyrophosphate is a coenzyme and the active form of vitamin B. It functions as coenzyme in decarboxylation of a-keto acid and in hexose monophosphate shunt. 

The answer is a. (Murray, pp 627-661. Scriver, pp 3897-3964. Sack, pp 121—138. Wilson, pp 287-320.) The major contributor of electrons in reductive biosynthetic reactions is nicotinamide adenine dinucleotide phosphate (NADPH -I- H ), which is derived by reduction of NAD. NAD is formed from the vitamin niacin (also called nicotinate). Niacin can be formed from tryptophan in humans. In the synthesis of NAD, niacin reacts with 5-phosphoribosyl-l-pyrophosphate to form nicotinate ribonucleotide. Then, AMP is transferred from ATP to nicotinate ribonucleotide. Finally, the amide group of glutamate is transferred to the niacin carboxyl group to form the final product, NAD. NADP is derived from NAD by phosphorylation of the 2 -hydroxyl group of the adenine ribose moiety. The reduction of NADP to NADPH -I- H occurs primarily through the hexose monophosphate shunt. 

Kaplan and Basford (1976) have examined neutrophil function in three patients with megaloblastic anemia due to folic acid deficiency. In vitro tests of PMN function they observed no change in phagocytosis associated hexose monophosphate enzyme levels or in microbicidal activity. Four patients with vitamin BJ2 deficiency showed significant impairment of these parameters. 

Kaplan and Basford (1976) in their study of neutrophil function in four patients with megloblastic anemia showed that resting levels of hexose monophosphate shunt activities were slightly lower in PMN leukocytes from patients with vitamin Bi2 deficiency. However, when challenged with the latex beads or staphylococci, HMPS activity was only 1/3 that of controls. There was no impairment in leukocytes from patients with folic acid deficiency. Microbicidal activity was also slightly decreased in... 

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