Carbonyl reductase 3 catalyzes the reduction of a large number of biologically and pharmacologically active carbonyl compounds to their corresponding alcohols. The enzyme is classified as a monomeric NADPH-dependent oxidoreductase. CBR3 contains three exons spanning 11.2 kilobases and is closely linked to another carbonyl reductase gene - CBR1. Carbonyl reductase (CBR) catalyzes the reduction of a large number of biologically and pharmacologically active carbonyl compounds to their corresponding alcohols. By analyzing sequences from the 21q22.2 chromosomal region, Watanabe et al. (1998) identified genomic clones corresponding to CBR1 and to CBR3, a novel carbonyl reductase gene. The deduced 277-amino acid CBR3 protein is 84% similar to the CBR1 protein.