19R-Hydroxyprostaglandins are major components of human seminal fluid. They are apparently formed in the seminal vesicles by NADPH-dependent omega2-hydroxylation. The hydroxylase is likely a cytochrome P450 (CYP), which has not been identified. To address this issue we studied gene expression of CYPs in human seminal vesicles (n = 4) with reverse-transcription polymerase chain reaction (RT-PCR). CYP1B1, CYP2E1, CYP2J2, CYP3A5, CYP4B1, and CYP4B1 with insertion of three nucleotides (Ser207) were detected in all subjects. RT-PCR with degenerate primers for the CYP4 family yielded a novel cDNA sequence, which was derived from a previously reported genomic sequence on chromosome 19p13.1 and present in all subjects. cDNA cloning showed that the deduced amino acid sequence consisted of 520 amino acids. Northern blot analysis demonstrated mRNA transcripts of approximately 2.1 and approximately 2.3 kb. The deduced protein showed 81.2 and 76.7% amino acid identity with the human enzymes CYP4F2 and CYP4F3. The novel CYP was designated CYP4F8.
Copyright 1999 Academic Press.