Overexpression of human CYP4Z1, a cytochrome P450 enzyme, has been correlated with poor prognosis in human cancer. However, its catalytic properties are not yet known. We expressed this P450 in Schizosaccharomyces pombe and demonstrate by whole-cell biotransformation assays CYP4Z1-dependent in-chain hydroxylation of lauric and myristic acid, which in both cases leads to the formation of four different monohydroxylated products at positions omega-2, omega-3, omega-4, and omega-5, respectively. The CYP4Z1-expressing fission yeast should be a new valuable tool for testing cancer drugs or for the development of new prodrug strategies.