Linked Life Data

8068655

Source:http://linkedlifedata.com/resource/pubmed/id/8068655

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
32
pubmed:dateCreated
1994-9-29
pubmed:abstractText
The effects of camphor and camphor analogues on the CO recombination kinetics of ferrous cytochrome P450CAM (P450CAM) at 293 K have been studied as a function of hydrostatic pressure (0.1-200 MPa) by means of flash photolysis. At 0.1 MPa, the association rate constant (kon) for substrate-free P450CAM is 8.5 x 10(6) M-1 s-1. Measurements as a function of pressure lead to a determination of the activation volume (delta V not equal to) of +4 cm3 mol-1 for substrate-free protein. This positive delta V not equal to is interesting because the CO association reaction of various hemoproteins, such as myoglobin and hemoglobin, exhibit negative delta V not equal to values [Adachi, S., & Morishima, I. (1989) J. Biol. Chem. 264, 18896-18901; Unno, M., Ishimori, K., & Morishima, I. (1990) Biochemistry 29, 10199-10205]. The binding of d-camphor and some camphor analogues (d-fenchone, 3-endo-bromocamphor, and 3,3,5,5-tetramethylcyclohexanone) into the heme pocket strongly influences the kinetics, i.e., kon is reduced ((1-10) x 10(5) M-1 s-1) and delta V not equal to is altered to a negative value (-14 to -32 cm3 mol-1). The negative delta V not equal to suggests that the effects of camphor and these camphor analogues are due to an increase in the iron-ligand bond formation barrier. On the other hand, the binding of adamantane and norcamphor does not affect the kinetics. This result is particularly surprising because both substrate analogues are located in the immediate vicinity of the CO binding site.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
16
pubmed:volume
33
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
9762-8
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
High-pressure flash photolysis study of hemoprotein: effects of substrate analogues on the recombination of carbon monoxide to cytochrome P450CAM.
pubmed:affiliation
Division of Molecular Engineering, Graduate School of Engineering, Kyoto University, Japan.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't