Question

Which of the following conversions in glycolysis is an example of substrate level phosphorylation?

• A. Glyceraldehyde -3-phosphate to 1, 3-bisphosphoglycerate
• B. 1, 3-bisphosphoglycerate to 3-phosphoglycerate
• C. Fructose 6-phosphate to fructose-1, 6-bisphosphate
• D. Glucose-6-phosphate to fructose-6-phosphate

Answer 1

Answer: (B)

The conversion of $1,3$ -bisphosphoglycerate to $3$ -phosphoglycerate is an example of substrate level phosphorylation. ATP is produced in this reaction.
$1,3$ -bisphosphoglycerate $+$ ADP
$\underset{\text{Kinase}}{\overset{\text{Phosphoglycerate}}{\rightleftharpoons }}3$-phosphoglycerate $+$ ATP
In this process, high energy phosphate group is transferred from $1,3$
bisphosphoglycerate which results in the formation of ATP.
This ATP formation is referred as substrate level phosphorylation because the phosphate donor $1,3$
bisphosphoglycerate is a substrate.