Short chain dehydrogenase/reductase family 16C, member5, also known as SDR16C5, is active in both the oxidative and reductive directions. This protein oxidizes all-trans-retinol in all-trans-retinaldehyde. No activity was detected with 11-cis-retinol or 11-cis-retinaldehyde as substrates with either NAD+/NADH or NADP+/NADPH. Recombinant human SDR16C5 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.