The key regulatory enzyme in hepatic biosynthesis of heme is
Correct Answer: ALA synthase
Description: ALA Synthase Is the Key Regulatory Enzyme in Hepatic Biosynthesis of HemeThere are two isozymes of ALA synthase. ALAS1 is expressed throughout the body; ALAS2 is expressed in erythrocyte precursor cells.The reaction catalyzed by ALA synthase 1 is rate-limiting for biosynthesis of heme in liver. It appears that heme, probably acting through an aporepressormolecule, acts as a negative regulator of the synthesis ofALAS1 The rate of synthesis of ALAS1 thus increases greatly in the absence of heme but diminishes in its presence.Heme also affects translation of the enzyme and its transfer from the cytosol to the mitochondrion. ALAS1 has a sho half-life, which is typical for an enzyme that catalyzes a rate-limiting reaction.Reference: Harper biochemistry, 30th edition, page no 326
Category:
Biochemistry
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now