Which activated sulfate donor supplies the sulfate group for Phase II sulfotransferase reactions?
- A S-adenosylmethionine
- B UDP-glucuronic acid
- C 3'-phosphoadenosine-5'-phosphosulfate (PAPS) ✓
- D Acetyl coenzyme A
Correct answer: C. 3'-phosphoadenosine-5'-phosphosulfate (PAPS)
Explanation
PAPS, synthesised from ATP and inorganic sulfate in two steps, is the universal sulfate donor for sulfotransferases acting on phenols, alcohols, amines and steroid hormones. UDP-glucuronic acid serves glucuronidation and acetyl-CoA serves acetylation, so those donors belong to different conjugation systems. Sulfation products are highly water soluble but the pool of PAPS is small and saturable at high substrate loads.
Reference: Harper's Illustrated Biochemistry, 32nd ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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