CBR3, also known as hCBR3, belongs to the short-chain dehydrogenases/reductases (SDR) family. CBR3 is expressed in ovary, pancreas, intestine, colon, kidney, brain, thymus, lung, heart, liver, spleen, leukocyte, prostate and testis. It is a monomeric NADPH-dependent oxidoreductase and is closely linked to another carbonyl reductase gene – CBR1. CBR3 catalyzes the reduction of a large number of biologically and pharmacologically active carbonyl compounds to their corresponding alcohols. It has low NADPH-dependent oxidoreductase activity towards 4-benzoylpyridine and menadione (in vitro).