The immediate precursor of mevalonic acid is: (A) Mevalonyl CoA, (B) Mevalonyl pyrophosphate, (C) Acetoacetyl CoA, (D) Beta hydroxy-beta methyglutaryl CoA
Answer is D. Beta-hydroxy beta-methyl glutaryl CoA (HMG CoA). The reduction of HMG CoA to mevalonate is catalysed by HMG CoA reductase. It is a microsomal (endoplasmic reticulum) enzyme.Ref: DM Vasudevan - Textbook of Biochemistry, 8th edition, page no: 148