FATTY-ACID HYDROXYLASE OF THE FUNGUS FUSARIUM-OXYSPORUM IS POSSIBLY AFUSED PROTEIN OF CYTOCHROME-P-450 AND ITS REDUCTASE

Fatty acid subterminal (omega-1-omega-3) hydroxylase of the fungus Fus arium oxysporum was solubilized from the microsomal fraction and parti ally purified. The hydroxylase activity was recovered into a single ac tive fraction, and its spectral nature showed the presence of cytochro me P-450 (P-450). Fatty acid hydroxylase activity was markedly restore d upon addition of FAD, FMN, and/or hemine to the eluted fraction. The fraction also exhibited other properties characteristic of both a hem eprotein and a flavin-containing reductase. These results are highly i ndicative that the fungal hydroxylase is a fused protein containing bo th P-450 and its reductase domains. In this aspect the fungal enzyme r esembles bacterial P-450(BM3), although it is membrane-bound unlike th e bacterial counterpart, (C) 1994 Academic Press, Inc.