Biomaterial Database

Properties of aryl hydrocarbon (benzo[alpha]pyrene) hydroxylase in lung microsomes of mice. 1978

M Watanabe, and K Konno, and H Sato

The activity of aryl hydrocarbon hydroxylase (AHH) in the lung from C3H/He and DBA/2 strains of mice was apparently increased by the oral administration of benzo[alpha]pyrene, but the enzyme activity in the liver was not. Properties of AHH enzymes in the lung microsomes from mice treated intraperitoneally with 3-methylcholanthrene (induced enzymes) were compared with those treated with corn oil (constitutive enzymes). The two enzymes were similar in pH-activity curve and the apparent Km for NADPH or NADH, but differed in the apparent Km for benzo[alpha]pyrene; the value for the induced enzyme (6micron) being lower than that for the constitutive enzyme (25 micron). Both 5,6- and 7,8-benzoflavones and 2,2'-bipyridine inhibited the activity of the two enzymes similarly, but N-benzyl-N,alpha-dimethylphenethylamine hydrochloride and 2-diethylaminoethyl diphenylpropylacetate inhibited the activity of the constitutive enzyme more severely than that of the induced enzyme. Cyclohexene oxide, 1,1,1-trichloropropane oxide, and leupeptin inhibited the activity of the constitutive enzyme slightly, but enhanced the activity of the induced enzyme. The significance of these differences was discussed briefly in relation to the carcinogenicity of polycyclic hydrocarbons.

UI	MeSH Term	Description	Entries
D007976	Leupeptins	A group of acylated oligopeptides produced by Actinomycetes that function as protease inhibitors. They have been known to inhibit to varying degrees trypsin, plasmin, KALLIKREINS, papain and the cathepsins.
D008099	Liver	A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.	Livers
D008861	Microsomes	Artifactual vesicles formed from the endoplasmic reticulum when cells are disrupted. They are isolated by differential centrifugation and are composed of three structural features: rough vesicles, smooth vesicles, and ribosomes. Numerous enzyme activities are associated with the microsomal fraction. (Glick, Glossary of Biochemistry and Molecular Biology, 1990; from Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)	Microsome
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
D009538	Nicotine	Nicotine is highly toxic alkaloid. It is the prototypical agonist at nicotinic cholinergic receptors where it dramatically stimulates neurons and ultimately blocks synaptic transmission. Nicotine is also important medically because of its presence in tobacco smoke.	Nicotine Bitartrate,Nicotine Tartrate
D011335	Proadifen	An inhibitor of drug metabolism and CYTOCHROME P-450 ENZYME SYSTEM activity.	Propyladiphenin,Diethylaminoethyldiphenylpropyl Acetate,Proadifen Hydrochloride,SK&F-525-A,SK-525A,SKF-525-A,SKF-525A,Acetate, Diethylaminoethyldiphenylpropyl,Hydrochloride, Proadifen,SK 525A,SK&F 525 A,SK&F525A,SK525A,SKF 525 A,SKF525A
D011725	Pyridines	Compounds with a six membered aromatic ring containing NITROGEN. The saturated version is PIPERIDINES.
D002413	Cations, Divalent	Positively charged atoms, radicals or groups of atoms with a valence of plus 2, which travel to the cathode or negative pole during electrolysis.	Divalent Cations
D003510	Cyclohexanes	Six-carbon alicyclic hydrocarbons.
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