Which of the following enzymes are not linked correctly based on their functions?
Select one
a) lsomerase-alanine racemase
B) Ligase-argininosuccinate synthetase
c. Ligase-methyltransferase
D) Oxidoreductase - alcohol dehydrogenase
Answers
Answer:
B) Ligase - Arignionosuccinate synthetase.
Answer:
The following enzymes are not linked correctly based on their functions Ligase-argininosuccinate synthetase
Explanation:
In the first step of the catalyzed reaction, citrulline attacks the α-phosphate of ATP to form citrulline adenylate, a reactive intermediate. The attachment of AMP to the ureido (urea-like) group on citrulline activates the carbonyl center for subsequent nucleophilic attack. This activation facilitates the second step, in which the α-amino group of aspartate attacks the ureido group. Attack by aspartate is the rate-limiting step of the reaction. This step produces free AMP and L-argininosuccinate.
Tthermodynamically, adenylation of the citrulline ureido group is more favorable than the analogous phosphorylation. Additionally, an attack by citrulline at the α-phosphate of ATP produces an equivalent of pyrophosphate, which can be hydrolyzed in a thermodynamically favorable reaction to provide additional energy to drive the adenylation.
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