Ranking compounds by their standard free energy of hydrolysis, which of the following has the highest phosphate group transfer potential?
- A Glucose 6 phosphate
- B Glycerol 3 phosphate
- C Phosphoenolpyruvate ✓
- D Creatine phosphate
Correct answer: C. Phosphoenolpyruvate
Explanation
Phosphoenolpyruvate has the highest transfer potential of all common biological phosphates (delta G0 prime of hydrolysis about minus 61.9 kJ/mol) because hydrolysis releases the trapped enol form of pyruvate, which tautomerises spontaneously to the far more stable keto form. Creatine phosphate ranks next, followed by ATP. Glucose 6 phosphate and glycerol 3 phosphate are simple phosphate esters with much lower potentials and cannot phosphorylate ADP.
Reference: Lehninger Principles of Biochemistry (Nelson and Cox), 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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