Linked Life Data

7625841

Source:http://linkedlifedata.com/resource/pubmed/id/7625841

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1995-8-28
pubmed:abstractText
Pressure-induced changes in ferric P450 2B4 (LM2) were studied as a function of benzphetamine concentration (0.05 divided by 2 mM) and state of aggregation of the hemoprotein in solution. Application of factor analysis to the spectral changes in the Soret region allowed us to resolve two particular pressure-induced processes in 2B4 oligomers. The first process was identified as the conversion of the low-spin P450 into the P420 state. At 25 degrees C it was followed by decay (bleaching) of about 50% of the newly formed P420. The second process was a pressure-induced high- to low-spin shift. Both transitions were reversible, except the hemoprotein bleaching. The amplitude of the P450-->P420 transition accounted for 67 +/- 5% of the total hemoprotein content. Furthermore, the fraction of the hemoprotein exposed to spin equilibrium was not affected by the P450-->P420 conversion and was estimated to be only about 31 +/- 5% of the total hemoprotein content. After the dissociation of the oligomers by 0.2% Triton N-101, the inhomogeneity vanished: 95% of the monomers were involved in the P450-->P420 transition (delta V degrees = -86 ml/mol) followed by intense bleaching of the hemoprotein. This agrees with our earlier observations on the reduced carbonyl complex of P450 2B4 and suggests some conformational difference between subunits in P450 LM2 oligomers. The parameters of the P450-->P420 conversion (delta V degrees = -32 ml/mol, P1/2 = 1560 bar) show no dependency on the substrate concentration. Analysis of the pressure-induced spin shift versus benzphetamine concentration shows this transition to be caused mainly by changes in the spin equilibrium of both substrate-bound (delta V degrees = -49 ml/mol) and substrate-free (delta V degrees = -21 ml/mol) hemoprotein, whereas the substrate binding step itself has a very weak pressure dependency (delta V degrees = -8 ml/mol).
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0003-9861
pubmed:author
pubmed:issnType
Print
pubmed:day
10
pubmed:volume
320
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
330-44
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
High-pressure-induced transitions in microsomal cytochrome P450 2B4 in solution: evidence for conformational inhomogeneity in the oligomers.
pubmed:affiliation
Institut de Biologie Physico-Chimique, INSERM U.310, Paris, France.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't