Identification and tissue distribution of the novel human cytochrome P4502S1 (CYP2S1)

With the aid of the htgs and dbEST databases, a novel cytochrome P450 cDNA was found by homology searches, and the corresponding gene was identified o n chromosome 19. Nested PCR was used to amplify a full-length sequence of 1 515 bp. The predicted 504 amino acid sequence displays 38-49% identity with CYP2 family members and the protein was designated CYP2S1. mRNA dot blot a nalysis demonstrated high expression levels in trachea, lung, stomach, smal l intestine, and spleen. The expression pattern was confirmed by Northern b lot, which also revealed a single transcript of approximately 2.4 kb. Weste rn blot analysis, using an antiserum directed against the C-terminus of the enzyme, detected a protein in human lung with the same mobility as recombi nant CYP2S1. Subcellular fractionation and immunostaining revealed that CYP 2S1 was localized in the endoplasmic reticulum. We conclude that CYP2S1 rep resents a novel abundantly expressed human P450 with potential importance f or extrahepatic xenobiotic metabolism. (C) 2001 Academic Press.