Linked Life Data

8931549

Source:http://linkedlifedata.com/resource/pubmed/id/8931549

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
46
pubmed:dateCreated
1997-1-7
pubmed:abstractText
Cytochrome P450cam was subjected to high pressures of 2.2 kbar, converting the enzyme to its inactive form P420cam. The resultant protein was characterized by electron paramagnetic resonance, magnetic circular dichroism, circular dichroism, and electronic absorption spectroscopy. A range of exogenous ligands has been employed to probe the coordination structure of P420cam. The results suggest that conversion to P420cam involves a conformational change which restricts the substrate binding site and/or alters the ligand access channel. The reduction potential of P420cam is essentially the same in the presence or absence of camphor (-211 +/- 10 and -210 +/- 15 mV, respectively). Thus, the well-documented thermodynamic regulation of enzymatic activity for P450cam in which the reduction potential is coupled to camphor binding is not found with P420cam. Further, cyanide binds more tightly to P420cam (Kd = 1.1 +/- 0.1 mM) than to P450cam (Kd = 4.6 +/- 0.2 mM), reflecting a weakened iron-sulfur ligation. Spectral evidence reported herein for P420cam as well as results from a parallel investigation of the spectroscopically related inactive form of chloroperoxidase lead to the conclusion that a sulfur-derived proximal ligand is coordinated to the heme of ferric cytochrome P420cam.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
19
pubmed:volume
35
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
14530-6
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
Probing the heme iron coordination structure of pressure-induced cytochrome P420cam.
pubmed:affiliation
Department of Biochemistry, School of Chemical Sciences, University of Illinois, Urbana 61801, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't