Linked Life Data

17503787

Source:http://linkedlifedata.com/resource/pubmed/id/17503787

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
31
pubmed:dateCreated
2007-8-2
pubmed:abstractText
We studied proposed steps for the enzymatic formation of gamma-carboxyglutamic acid by density functional theory (DFT) quantum chemistry. Our results for one potentially feasible mechanism show that a vitamin K alkoxide intermediate can abstract a proton from glutamic acid at the gamma-carbon to form a carbanion and vitamin K epoxide. The hydrated carbanion can then react with CO2 to form gamma-carboxyglutamic acid. Computations at the B3LYP/6-311G** level were used to determine the intermediates and transition states for the overall process. The activation free energy for the gas-phase path is 22 kcal/mol, with the rate-limiting step for the reaction being the attack of the carbanion on CO2. Additional solvation studies, however, indicate that the formation of the carbanion step can be competitive with the CO2 attack step in high-dielectric systems. We relate these computations to the entire vitamin K cycle in the blood coagulation cascade, which is essential for viability of vertebrates.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
1089-5639
pubmed:author
pubmed:issnType
Print
pubmed:day
9
pubmed:volume
111
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
7257-61
pubmed:dateRevised
2007-12-3
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Quantum chemical study of the mechanism of action of vitamin K carboxylase (VKC). IV. Intermediates and transition states.
pubmed:affiliation
Department of Biochemistry, University of North Carolina, Chapel Hill, North Carolina 27599, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, N.I.H., Extramural