QUESTION 13 The following reaction is catalyzed by the enzyme Carbamoyl phosphate Synthetase II: Carbonate + 2 ATP + Glutamine + H?O ? Carbamoyl phosphate + Glutamate + 2 ADP + Pi + H? H?O + ?H?N-C-H CH? CH? H?N-C=O Glutamine ? ?H?N-C-H CH? CH? -O-C=O Glutamate + HO-P=O + H? O=C-O? Carbonate from CO? + ATP ? ADP Step #1 ? HO-P-O-C-OH OH Carbonate-phosphate anhydride ? Step #2 ? H?N-C-O? Carbamate ? Step #3 (ATP ? ADP) ? Carbamoyl phosphate H?N-C-O-P-O? Carbamoyl phosphate Synthetase generates the HEI carbamoyl phosphate. It is considered an ‘intermediate’ even though it’s shown as the product of the reaction. Carbamoyl phosphate is used to synthesize N-carbamoylaspartate in subsequent reactions to ultimately generate the pyrimidine bases of DNA/RNA. (a) Why is carbamoyl phosphate considered a HEI? (b) There are two other intermediates formed in this reaction, carbonate-phosphate anhydride and carbamate. Which has higher energy? Why?
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Step 1: Formation of carbamate from glutamine and bicarbonate Show more…
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