Biomaterial Database

Rat liver microsomal cytochrome P-450 responsible for reductive metabolism of zonisamide. 1993

H Nakasa, and M Komiya, and S Ohmori, and T Rikihisa, and M Kitada

Division of Pharmacy, Chiba University Hospital, Faculty of Medicine, Japan.

The reductive metabolism of 1,2-benzisoxazole-3-methanesulfonamide (zonisamide) to 2-sulfamoylacetylphenol (SMAP) was observed in liver microsomes from female rats, as well as male rats, but the SMAP-producing activity in female rats was 4-fold lower than that found in male rats. In addition, the reductive metabolism of zonisamide in liver microsomes was induced by the treatment of male rats with phenobarbital. However, the SMAP-producing activity did not correlate positively with the amounts of P-450 2B1 and P-450 2C11 immunochemically determined. In contrast, the reductive metabolism of zonisamide was also found to be induced by the pretreatment of male rats with pregnenolone 16 alpha-carbonitrile, triacetyloleandomycin, and dexamethasone. Furthermore, the SMAP-producing activity correlated highly with the amount of P-450 cross-reactive with antihuman P-450 3A4 antibody, suggesting that P-450 3A1/2 may function in the reductive metabolism of zonisamide. In addition, the P-450 PCNa (3A2) exhibited the SMAP-producing activity in a reconstituted system. The antihuman P-450 3A4 antibody inhibited markedly the formation of SMAP from zonisamide in male rat liver microsomes. These results indicate that cytochrome(s) P-450 belonging to P-450 3A subfamily may be predominantly responsible for the reductive metabolism of zonisamide in rat liver microsomes.

UI	MeSH Term	Description	Entries
D007555	Isoxazoles	Azoles with an OXYGEN and a NITROGEN next to each other at the 1,2 positions, in contrast to OXAZOLES that have nitrogens at the 1,3 positions.	Isoxazole
D008297	Male		Males
D008862	Microsomes, Liver	Closed vesicles of fragmented endoplasmic reticulum created when liver cells or tissue are disrupted by homogenization. They may be smooth or rough.	Liver Microsomes,Liver Microsome,Microsome, Liver
D010084	Oxidation-Reduction	A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).	Redox,Oxidation Reduction
D010636	Phenols	Benzene derivatives that include one or more hydroxyl groups attached to the ring structure.
D003577	Cytochrome P-450 Enzyme System	A superfamily of hundreds of closely related HEMEPROTEINS found throughout the phylogenetic spectrum, from animals, plants, fungi, to bacteria. They include numerous complex monooxygenases (MIXED FUNCTION OXYGENASES). In animals, these P-450 enzymes serve two major functions: (1) biosynthesis of steroids, fatty acids, and bile acids; (2) metabolism of endogenous and a wide variety of exogenous substrates, such as toxins and drugs (BIOTRANSFORMATION). They are classified, according to their sequence similarities rather than functions, into CYP gene families (>40% homology) and subfamilies (>59% homology). For example, enzymes from the CYP1, CYP2, and CYP3 gene families are responsible for most drug metabolism.	Cytochrome P-450,Cytochrome P-450 Enzyme,Cytochrome P-450-Dependent Monooxygenase,P-450 Enzyme,P450 Enzyme,CYP450 Family,CYP450 Superfamily,Cytochrome P-450 Enzymes,Cytochrome P-450 Families,Cytochrome P-450 Monooxygenase,Cytochrome P-450 Oxygenase,Cytochrome P-450 Superfamily,Cytochrome P450,Cytochrome P450 Superfamily,Cytochrome p450 Families,P-450 Enzymes,P450 Enzymes,Cytochrome P 450,Cytochrome P 450 Dependent Monooxygenase,Cytochrome P 450 Enzyme,Cytochrome P 450 Enzyme System,Cytochrome P 450 Enzymes,Cytochrome P 450 Families,Cytochrome P 450 Monooxygenase,Cytochrome P 450 Oxygenase,Cytochrome P 450 Superfamily,Enzyme, Cytochrome P-450,Enzyme, P-450,Enzyme, P450,Enzymes, Cytochrome P-450,Enzymes, P-450,Enzymes, P450,Monooxygenase, Cytochrome P-450,Monooxygenase, Cytochrome P-450-Dependent,P 450 Enzyme,P 450 Enzymes,P-450 Enzyme, Cytochrome,P-450 Enzymes, Cytochrome,Superfamily, CYP450,Superfamily, Cytochrome P-450,Superfamily, Cytochrome P450
D005260	Female		Females
D000078305	Zonisamide	A benzisoxazole and sulfonamide derivative that acts as a CALCIUM CHANNEL blocker. It is used primarily as an adjunctive antiepileptic agent for the treatment of PARTIAL SEIZURES, with or without secondary generalization.	3-Sulfamoylmethyl-1,2-benzisoxazole,AD 810,AD-810,CI 912,CI-912,Zonegran,Zonisamide Monosodium,3 Sulfamoylmethyl 1,2 benzisoxazole,AD810,CI912
D000693	Anaerobiosis	The complete absence, or (loosely) the paucity, of gaseous or dissolved elemental oxygen in a given place or environment. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)	Anaerobic Metabolism,Anaerobic Metabolisms,Anaerobioses,Metabolism, Anaerobic,Metabolisms, Anaerobic
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia