Several cytochrome P450-dependent fatty acid hydryoxylases from different plant sources have been identified by recombinant cloning technology and characterized structurally and functionally. These clones represent novel plant hydroxylases which are active when expressed in a heterologous yeast system. These hydroxylase enzymes hydroxylate fatty acid substrates at different, well-defined postions in acid substrates of various chain lengths. The hydroxylases catalyze epoxidation of fatty acids, natural and synthetic, bearing a double bond at the site of attack.