Linked Life Data

12010067

Source:http://linkedlifedata.com/resource/pubmed/id/12010067

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
20
pubmed:dateCreated
2002-5-15
pubmed:abstractText
The (t approximately 0) photodissociation quantum yields (Y(0)) of MbNO and MbO(2) are measured to be 50 +/- 5 and 28 +/- 6%, respectively, using MbCO (Y(0) = 100%) as a reference. When photolysis does not take place, we find that a significant portion of the photon energy contributes to heating of the residual six-coordinate heme (MbNO and MbO(2)). The time constant for vibrational relaxation of the six-coordinate ligand-bound heme is found to be close to 1 ps for both samples. The MbO(2) sample also shows a approximately 4-ps optical response that is assigned to a rapid phase (25-30% amplitude) of O(2) geminate rebinding. We observe no additional geminate recombination in the MbO(2) sample out to 120 ps. In contrast, the MbNO sample displays significant geminate recombination over the first 120 ps, which can be adequately fit with two exponentials whose amplitudes and time constants appear to depend weakly on the pump wavelength. This more complex kinetic behavior conceivably arises due to heating of the photodissociated heme and its effect on the geminate recombination as the system cools. Overall, the data are consistent with a hypothesis that distortions along the iron-ligand bending coordinate play a key role in the photodissociation process. The transient formation of an unphotolyzable FeO(2) side-on binding geometry is suggested to be responsible for the lowered quantum yield of MbO(2) relative to MbNO.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0002-7863
pubmed:author
pubmed:issnType
Print
pubmed:day
22
pubmed:volume
124
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
5914-24
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Measurements of the photodissociation quantum yields of MbNO and MbO(2) and the vibrational relaxation of the six-coordinate heme species.
pubmed:affiliation
Physics Department and Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, Massachusetts 02115, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.