The "major" phenobarbital (PB)-induced cytochrome P-450 species present in livers of male Sprague-Dawley rats was resolved into two catalytically active heme-protein fractions on diethylaminoethyl cellulose. The two species, P-450 PB-4 (Mr = 49,000) and P-450 PB-5 (Mr = 51,000), were purified to homogeneity, and their chromatographic, spectral, catalytic, and structural properties were compared...

The role of TPNH as the donor of reducing equivalents to microsomal mixed function oxidations of drugs, other foreign compounds, and steroids in the liver is well established (1-5). DPNH will not substitute for TPNH in the cyt#{243}chrome P-450-mediated oxidation of drugs, but reaction rates are increased when both nucleotides are present (61 1 ). Although this synergistic role of DPNH has been...

A simple metinod for tine determinations, by ligannd binndinug to octylaminie, of tine absolute amounts of inigharid loss--spins formsss of huemoproteini P-450 of rabbit liver microsomcs is described. A correlationn betus-eenn octvlrsminse bimsdinsg to tine two forms of oxidized P-450 and the binsdinsg of ethyl isocyanide to reduced P-450 inas beeni observed, and advantages of tine aminc-binidi...

The potent porphyrogen allylisopropylacetamide and related compounds decrease hepatic concentrations of cytochrome P-450. This decrease occurs particularly in phenobarbital-induced cytochrome P-450 and is caused by suicidal breakdown of the haem of cytochrome P-450. Quantitative rocket immunoelectrophoresis showed that the protein moiety of the major phenobarbital-inducible form of hepatic cyto...

Although cytochrome P-450 monoxygenases mediate critical reactions in plant microsomes, characterization of their activities has been difficult due to their inherent instability and the lack of a crossreacting P-450 antibody. We have surveyed the effects of protein stabilizing agents on t-cinnamic acid hydroxylase (t-CAH), a prominent microsomal P-450, and on total P-450 monoxygenase content. T...

Methods for the isolation and spectrophotometric determination of cytochrome P-450 in mycobacteria were standardized. Cytochrome P-450 levels were estimated in Mycobacterium tuberculosis organisms sensitive to both isoniazid and rifampicin and resistant to any of the two drugs. Cytochrome P-450 was isolated and its presence was shown in M. smegmatis, M. fortuitum, M. chelonae and M. tuberculosi...

Monoclonal antibody (MAb)-based radioimmunoassay (RIA) and immunopurification procedures were used to probe the immunochemical relatedness of cytochromes P-450 in tissues from different species. RIAs based on MAb 1-7-1 and MAb 1-31-2, both to the major 3-methylcholanthrene (MC)-induced rat liver microsomal cytochrome P-450, detected antigenically related forms of cytochrome P-450 in liver micro...

Using the stereospecific metabolism of (+)- and (-)-bufuralol and (+)- and (-)-metoprolol as model reactions, we have characterized the enzymic deficiency of the debrisoquine/sparteine-type polymorphism by comparing kinetic data of subjects in vivo with their microsomal activities in vitro and with reconstituted activities of cytochrome P-450 isozymes purified from human liver. The metabolism o...

Glycerol can be oxidized to formaldehyde by microsomes in a reaction that is dependent on cytochrome P-450. An oxidant derived from the interaction of H2O2 with iron was responsible for oxidizing the glycerol, with P-450 suggested to be necessary to produce H2O2 and reduce non-haem iron. The effect of paraquat on formaldehyde production from glycerol and whether paraquat could replace P-450 in ...