Substrate level phosphorylation occur in step catalysed by which of the following enzyme in TCA cycle?

Succinate thiokinase is the enzyme that generates ATP directly by substrate-level phosphorylation. In Krebs cycle succinate thiokinase catalyze the conversion of Succinyl CoA into succinate. In this step GDP is phosphorylated to GTP. GTP can then be conveed to ATP by reacting with an ADP molecule. Substrate-level phosphorylation is a type of metabolism that results in the formation and creation of adenosine triphosphate (ATP) or guanosine triphosphate (GTP) by the direct transfer and donation of a phosphoryl (P03) group to adenosine diphosphate (ADP) or guanosine diphosphate (GDP) from a phosphorylated reactive intermediate. In glycolysis substrate level phosphorylation occur in two steps: Conversion of 1,3 BPG to 3 Phosphoglycerate catalyzed by Phosphoglycerate kinase Conversion of Phosphoenolpyruvate to pyruvate catalyzed by Pyruvate kinase Ref: Textbook of Biochemistry By D M Vasudevan, 3rd Edition, Page 195