| pubmed-article:19552441 | rdf:type | pubmed:Citation | lld:pubmed |
| pubmed-article:19552441 | lifeskim:mentions | umls-concept:C0026336 | lld:lifeskim |
| pubmed-article:19552441 | lifeskim:mentions | umls-concept:C0010762 | lld:lifeskim |
| pubmed-article:19552441 | lifeskim:mentions | umls-concept:C0534137 | lld:lifeskim |
| pubmed-article:19552441 | lifeskim:mentions | umls-concept:C0205332 | lld:lifeskim |
| pubmed-article:19552441 | lifeskim:mentions | umls-concept:C0205250 | lld:lifeskim |
| pubmed-article:19552441 | lifeskim:mentions | umls-concept:C0205198 | lld:lifeskim |
| pubmed-article:19552441 | pubmed:issue | 28 | lld:pubmed |
| pubmed-article:19552441 | pubmed:dateCreated | 2009-7-15 | lld:pubmed |
| pubmed-article:19552441 | pubmed:abstractText | The detection and kinetic characterization of a cytochrome P450 model compound I, [OFe(IV)-4-TMPyP](+) (1), in aqueous solution shows extraordinary reaction rates for C-H hydroxylations. Stopped-flow spectrophotometric monitoring of the oxidation of Fe(III)-4-TMPyP with mCPBA revealed the intermediate 1, which displays a weak, blue-shifted Soret band at 402 nm and an absorbance at 673 nm, typical of a porphyrin pi-radical cation. This intermediate was subsequently transformed into the well-characterized OFe(IV)-4-TMPyP. Global analysis afforded a second-order rate constant k(1) = (1.59 +/- 0.06) x 10(7) M(-1) s(-1) for the formation of 1 followed by a first-order decay with k(2) = 8.8 +/- 0.1 s(-1). (1)H and (13)C NMR determined 9-xanthydrol to be the major product (approximately 90% yield) of xanthene oxidation by 1. Electrospray ionization mass spectrometry carried out in 47.5% (18)OH(2) indicated 21% (18)O incorporation, consistent with an oxygen-rebound reaction scenario. Xanthene/xanthene-d(2) revealed a modest kinetic isotope effect, k(H)/k(D) = 2.1. Xanthene hydroxylation by 1 occurred with a very large second-order rate constant k(3) = (3.6 +/- 0.3) x 10(6) M(-1) s(-1). Similar reactions of fluorene-4-carboxylic acid and 4-isopropyl- and 4-ethylbenzoic acid also gave high rates for C-H hydroxylation that correlated well with the scissile C-H bond energy, indicating a homolytic hydrogen abstraction transition state. Mapping the observed rate constants for C-H bond cleavage onto the Brønsted-Evans-Polanyi relationship for similar substrates determined the H-OFe(IV)-4-TMPyP bond dissociation energy to be approximately 100 kcal/mol. The high kinetic reactivity observed for 1 is suggested to result from a high porphyrin redox potential and spin-state-crossing phenomena. More generally, subtle charge modulation at the active site may result in high reactivity of a cytochrome P450 compound I. | lld:pubmed |
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| pubmed-article:19552441 | pubmed:language | eng | lld:pubmed |
| pubmed-article:19552441 | pubmed:journal | http://linkedlifedata.com/r... | lld:pubmed |
| pubmed-article:19552441 | pubmed:citationSubset | IM | lld:pubmed |
| pubmed-article:19552441 | pubmed:chemical | http://linkedlifedata.com/r... | lld:pubmed |
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| pubmed-article:19552441 | pubmed:status | MEDLINE | lld:pubmed |
| pubmed-article:19552441 | pubmed:month | Jul | lld:pubmed |
| pubmed-article:19552441 | pubmed:issn | 1520-5126 | lld:pubmed |
| pubmed-article:19552441 | pubmed:author | pubmed-author:GrovesJohn... | lld:pubmed |
| pubmed-article:19552441 | pubmed:author | pubmed-author:BellSeth RSR | lld:pubmed |
| pubmed-article:19552441 | pubmed:issnType | Electronic | lld:pubmed |
| pubmed-article:19552441 | pubmed:day | 22 | lld:pubmed |
| pubmed-article:19552441 | pubmed:volume | 131 | lld:pubmed |
| pubmed-article:19552441 | pubmed:owner | NLM | lld:pubmed |
| pubmed-article:19552441 | pubmed:authorsComplete | Y | lld:pubmed |
| pubmed-article:19552441 | pubmed:pagination | 9640-1 | lld:pubmed |
| pubmed-article:19552441 | pubmed:dateRevised | 2011-1-20 | lld:pubmed |
| pubmed-article:19552441 | pubmed:meshHeading | pubmed-meshheading:19552441... | lld:pubmed |
| pubmed-article:19552441 | pubmed:meshHeading | pubmed-meshheading:19552441... | lld:pubmed |
| pubmed-article:19552441 | pubmed:meshHeading | pubmed-meshheading:19552441... | lld:pubmed |
| pubmed-article:19552441 | pubmed:meshHeading | pubmed-meshheading:19552441... | lld:pubmed |
| pubmed-article:19552441 | pubmed:meshHeading | pubmed-meshheading:19552441... | lld:pubmed |
| pubmed-article:19552441 | pubmed:meshHeading | pubmed-meshheading:19552441... | lld:pubmed |
| pubmed-article:19552441 | pubmed:meshHeading | pubmed-meshheading:19552441... | lld:pubmed |
| pubmed-article:19552441 | pubmed:meshHeading | pubmed-meshheading:19552441... | lld:pubmed |
| pubmed-article:19552441 | pubmed:year | 2009 | lld:pubmed |
| pubmed-article:19552441 | pubmed:articleTitle | A highly reactive p450 model compound I. | lld:pubmed |
| pubmed-article:19552441 | pubmed:affiliation | Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA. | lld:pubmed |
| pubmed-article:19552441 | pubmed:publicationType | Journal Article | lld:pubmed |
| pubmed-article:19552441 | pubmed:publicationType | Research Support, U.S. Gov't, Non-P.H.S. | lld:pubmed |
| pubmed-article:19552441 | pubmed:publicationType | Research Support, N.I.H., Extramural | lld:pubmed |
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