FURTHER CHARACTERIZATION OF HYDROGEN-PEROXIDE DEPENDENT FATTY-ACID ALPHA-HYDROXYLASE FROM SPHINGOMONAS-PAUCIMOBILIS

Although fatty acid cr-hydroxylase (FAAH) activity has been detected i n various species, FAAH has not been sufficiently characterized, In th is report, we describe the properties of FAAH highly purified from Sph ingomonas paucimobilis, The FAAH was purified by about 5,200-fold, Blo tting analysis with a specific antibody against the FAAH showed that i ts apparent molecular mass was approximately 43 kDa, FAAH showed alpha -hydroxylation activity in the presence of H2O2, but little if any act ivity with cumene hydroperoxide, t-butyl hydroperoxide, or t-butyl per oxybenzonate, The K-m value for H2O2 was 72 mu M. Highly purified FAAH oxidized various non-esterified saturated and unsaturated fatty acids including myristic acid, but not myristoyl-CoA, Potassium cyanide and sodium azide inhibited the FAAH activity in a concentration-dependent manner. Other respiratory chain inhibitors such as rotenone and antim ycin A did not inhibit the activity, Among cytochrome P450 inhibitors, SKF-525A markedly inhibited the activity at the concentration of 2 mM , but CO did not. Imidazole, an inhibitor of plant alpha-oxidation, sh owed no inhibitory effect at 1 mM.