Arsenate is structurally and chemically similar to inorganic phosphate (Pi), and many enzymes that require phosphate will also use arsenate. Organic compounds of arsenate are less stable than analogous phosphate compounds, however. For example, acyl arsenates decompose rapidly by hydrolysis: On the other hand, acyl phosphates, such as 1,3-bisphosphoglycerate, are more stable and undergo further enzyme-catalyzed transformation in cells. 1) Predict the effect on the net reaction catalyzed by glyceraldehyde 3-phosphate dehydrogenase if phosphate were replaced by arsenate.
A) The 1-arseno, 3-phosphoglycerate intermediate would decompose non- enzymatically, so no ATP would be formed in the phosphoglycerate kinase reaction.
B) Gluconeogenesis would be inhibited by arsenate because glyceraldehyde 3- L phosphate dehydrogenase is also an enzyme in that pathway.
C) The 1,3-bisphosphoglycerate intermediate would decompose non-enzymatically, so no NADH would be formed in the reaction.
D) There would be no net conversion of ADP to ATP from the conversion of glucose to pyruvate during glycolysis.
E) By substituting for phosphate in this reaction, the arsenate-containing compounds would inhibit several downstream reactions.
B) What would be the consequence to an organism if arsenate were substituted for phosphate? Arsenate is very toxic to most organisms. Explain why with special consideration of phosphoglycerate mutase?