The heteroteramer with HSD17B8 has NADH-dependent 3-ketoacyl-acyl carrier protein reductase activity. May play a role in biosynthesis of fatty acids in mitochondria. The homotetramer may act as NADPH-dependent quinone reductase. It has broad substrate specificity and reduces 9,10-phenanthrenequinone, 1,4-benzoquinone and various other o-quinones and p-quinones (in vitro). Synonyms: Polyclonal CBR4 antibody, Anti-CBR4 antibody, carbonyl reductase 4 antibody, FLJ14431 antibody, SDR45C1 antibody.