The cefF gene of Nocardia lactamdurans, encoding a functional 2-oxoglutarate-dependent 3-methylcephem hydroxylase (deacetoxycephalosporin C hydroxylase) has been found to be closely linked to the pcbC gene in the cephamycin C gene cluster. The open-reading frame is 933 bp long and could encode a protein of M _r 34366. Introduction of cefF in the cephamycin-non-producer Streptomyces lividans conferred 3-methylcephem-hydroxylating activity to the transformants but did not result in hydroxylation at carbon 7 of cephamycin. No 3-methylcephem hydroxylase activity was observed when the cefF gene was introduced in S. lividans in pIJ699 (a vector containing two transcriptional terminators that prevent read-through expression), which suggests that this gene lacks an independent promoter.