Linked Life Data

2271712

Source:http://linkedlifedata.com/resource/pubmed/id/2271712

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
51
pubmed:dateCreated
1991-2-27
pubmed:abstractText
A human liver cytochrome P-450 (P-450) IIIA4 cDNA clone was inserted behind an alcohol dehydrogenase promoter in the plasmid vector pAAH5 and expressed in Saccharomyces cerevisiae (D12 and AH22 strains). A cytochrome P-450 with typical spectral properties was expressed at a level of approximately 8 x 10(5) molecules/cell in either strain of yeast. The expressed P-450 IIIA4 had the same apparent monomeric Mr as the corresponding protein in human liver microsomes (P-450NF) and could be isolated from yeast microsomes. Catalytic activity of the yeast microsomes toward putative P-450 IIIA4 substrates was seen in the reactions supported by cumene hydroperoxide but was often lower and variable when supported by the physiological donor NADPH. The catalytic activity of purified P-450 IIIA4 was also poor in some systems reconstituted with rabbit liver NADPH-P-450 reductase and best when both the detergent 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate and a lipid extract (from liver or yeast microsomes) or L-alpha-1,2-dilauroyl-sn-glycero-3-phosphocholine were present. Under these conditions the expressed P-450 IIIA4 was an efficient catalyst for nifedipine oxidation, 6 beta-hydroxylation of testosterone and cortisol, 2-hydroxylation of 17 beta-estradiol and 17 alpha-ethynylestradiol, N-oxygenation and 3-hydroxylation of quinidine, 16 alpha-hydroxylation of dehydroepiandrosterone 3-sulfate, erythromycin N-demethylation, the 10-hydroxylation of (R)-warfarin, the formation of 9,10-dehydrowarfarin from (S)-warfarin, and the activation of aflatoxins B1 and G1, sterigmatocystin, 7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene (both + and - diastereomers), 3,4-dihydroxy-3,4-dihydrobenz[a]anthracene, 3,4-dihydroxy-3,4-dihydro-7, 12-dimethylbenz[a]anthracene, 9,10-dihydroxy-9,10-dihydrobenzo[b]fluoranthene, 6-aminochrysene, and tris(2,3-dibromopropyl) phosphate to products genotoxic in a Salmonella typhimurium TA1535/pSK1002 system where a chimeric umuC' 'lacZ plasmid is responsive to DNA alkylation. Reaction rates were stimulated by 7,8-benzoflavone and inhibited by rabbit anti-P-450 IIIA (anti-P-450NF), troleandomycin, gestodene, and cimetidine. Evidence was obtained that rates of reduction of ferric P-450 IIIA4 in yeast microsomes and the reconstituted systems are slow and at least partially responsible for the lower rates of catalysis seen in these systems (relative to liver microsomes). The results of these studies with a defined protein clearly demonstrate the ability of P-450 IIIA4 to catalyze regio- and stereoselective oxidations with a diverse group of substrates, and this enzyme appears to be one of the most versatile catalysts in the P-450 family.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
29
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
11280-92
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed-meshheading:2271712-Alcohol Dehydrogenase, pubmed-meshheading:2271712-Aryl Hydrocarbon Hydroxylases, pubmed-meshheading:2271712-Cloning, Molecular, pubmed-meshheading:2271712-Cytochrome P-450 Enzyme System, pubmed-meshheading:2271712-Gene Expression, pubmed-meshheading:2271712-Genetic Vectors, pubmed-meshheading:2271712-Humans, pubmed-meshheading:2271712-Kinetics, pubmed-meshheading:2271712-Liver, pubmed-meshheading:2271712-Microsomes, pubmed-meshheading:2271712-Microsomes, Liver, pubmed-meshheading:2271712-Plasmids, pubmed-meshheading:2271712-Promoter Regions, Genetic, pubmed-meshheading:2271712-Recombinant Fusion Proteins, pubmed-meshheading:2271712-Saccharomyces cerevisiae, pubmed-meshheading:2271712-Spectrophotometry, pubmed-meshheading:2271712-Steroid 16-alpha-Hydroxylase, pubmed-meshheading:2271712-Substrate Specificity
pubmed:year
1990
pubmed:articleTitle
Catalytic activities of human liver cytochrome P-450 IIIA4 expressed in Saccharomyces cerevisiae.
pubmed:affiliation
Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't