Catalyzes the reduction of 3-ketodihydrosphingosine (KDS) to dihydrosphingosine (DHS).
Subcellular locations: Endoplasmic reticulum membrane
Expressed in all tissues examined. Highest expression in placenta. High expression in lung, kidney, stomach and small intestine, low expression in heart, spleen and skeletal muscle. Weakly expressed in normal hematopoietic tissues. Higher expression in some T-cell malignancies and PHA-stimulated lymphocytes.