<prompt> The enzyme is the rate limiting enzyme in cholesterol synthesis is:HMG CoA synthetaseHMG CoA reductaseHMG CoA lyaseCatalase  <response>: Ans. b HMG CoA reductaseRef: Harpers Biochemistry, 30th ed. pg. 267 HMG CoA reductase is the rate limiting ezyme in cholesterol synthesis. HMG CoA Synthetase is involved in the formation of ketone bodies while HMG CoA lyase is involved also in the ketogenesis and also in the processing of leucine. Catalase on the other hand is an oxidoreductase which is involved in the conversion of hydrogen peroxide to water and oxygen. 