Question

Which one of the following molecules serves as a substrate for direct synthesis of ATP?

• A. $1,3$-biphosphoglycerate
• B. Glucose $6$-phosphate
• C. Pyruvate
• D. Fructose $1,6$-bisphosphate

Answer 1

Answer: (A)

$1,3$-biphosphoglycerate

Substrate-level phosphorylation results in the formation of ATP by the direct transfer of a phosphoryl group from another phosphorylated compound to ADP. Out of the given options, 1,3-bisphosphoglycerate serves as a substrate for direct synthesis of ATP. In this reaction, inorganic phosphate is transferred from from 1,3-bisphosphoglycerate to ADP to form ATP. This reaction is activated by enzyme phosphoglycerate kinase.

Thus, the correct answer is option A.