Inactivation of cytochrome cd1 by hydrazines.

Mechanism of inactivation of human cytochrome P450 2B6 by phencyclidine.

The mechanism behind the observed inactivation of human P450 2B6 by phencyclidine (PCP) has been evaluated over the past 2 decades. The scope of the current investigation was to contribute to the fundamental knowledge of PCP oxidation and perhaps the mechanism behind P450 inactivation. To study the chemistry of PCP oxidation, we subjected PCP to the Fenton reagent. Under Fenton chemistry condit...

Partial inactivation of cytochrome c oxidase by nonpolar mercurial reagents.

Purified beef heart cytochrome c oxidase is inactivated to the extent of 35 to 50% by the nonpolar mercurial reagents mercuric chloride and ethylmercuric chloride. The inactivation is complete within 5 min. In titrations of activity, the plateau level of inactivation is attained at added ethylmercuric chloride:heme a ratios of about 1:1. Up to 3 mercury atoms/heme a are bound to the oxidase, al...

Structural Plasticity and Function in Cytochrome cd1 Nitrite Reductase

Mechanism-based inactivation of cytochrome P450 3A4 by lapatinib.

Fatalities stemming from hepatotoxicity associated with the clinical use of lapatinib (Tykerb), an oral dual tyrosine kinase inhibitor (ErbB-1 and ErbB-2) used in the treatment of metastatic breast cancer, have been reported. We investigated the inhibition of CYP3A4 by lapatinib as a possible cause of its idiosyncratic toxicity. Inhibition of CYP3A4 was time-, concentration-, and NADPH-dependen...

Reversible Inactivation of Cytochrome Oxidase by Disulfide Bond Reagents.

Recent studies on the chemical nature of cytochrome oxidase (cytochrome c :02 oxidoreductase, EC 1.9.3.1) have been concerned largely with the structure of its iron-porphyrin prosthetic group (cj. (l)), the importance of copper as an integral component of the enzyme (e.g. (2-5)), and the possible role of a lipid factor (e.g. (6-8)). By contrast, little work has been done on the nature of the fu...