The cytochromes P450 (P450) constitute a family of hemeproteins that serve as monooxygenases for exogenous and endogenous substrates. The P4504A subfamily, consisting of eicosanoid and fatty acid hydroxylases, plays a role in the metabolism of arachidonic acid in lung, liver and kidney. This metabolism of arachidonic acid produces 20-hydroxyeicosatetraenoic acid (20-HETE), shown to be a potent vasoconstrictor and, consequently, could be involved in hemodynamic regulation (Sawamura et al., 1993). The P4504A family members from rabbit, 4A4, 4A5, 4A6, and 4A7, are 85% homologous in amino acid sequence but have been shown to exhibit differing substrate specificities (Roman et al., 1993). To determine the structural and functional characteristics of the P4504A7 substrate binding/recognition site, production of large amounts of enzyme in an E.coli expression was accomplished (20nmoles/liter) as a chimera with the first ten amino acids of bovine P45017a. Kinetic characterization determined that the primary substrate, lauric acid, was metabolized at a turnover number of 20min1, with a Km of 1.6nM. Characterization of other substrates will be presented.
|Original language||English (US)|
|State||Published - Dec 1 1997|
ASJC Scopus subject areas
- Molecular Biology