In enzymology, an acetoacetyl-CoA reductase is an enzyme that catalyzes the chemical reaction -3-hydroxyacyl-CoA + NADP+ ⇌ {\displaystyle \rightleftharpoons } 3-oxoacyl-CoA + NADPH + H+Thus, the two substrates of this enzyme are -3-hydroxyacyl-CoA and NADP+, whereas its 3 products are 3-oxoacyl-CoA, NADPH, and H+. Wikipedia