Linked Life Data

11749542

Source:http://linkedlifedata.com/resource/pubmed/id/11749542

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
51
pubmed:dateCreated
2001-12-25
pubmed:abstractText
Orotidine 5'-phosphate decarboxylase (ODCase) is the most proficient enzyme known, enhancing the rate of decarboxylation of orotidine 5'-phosphate (OMP) by a factor of 10(17), which corresponds to a DeltaDeltaG++ of approximately 24 kcal/mol. Ground-state destabilization through local electrostatic stress has been recently proposed as the basis of catalytic rate enhancement for a mechanism that is the same as in solution. We have carried out gas-phase ab initio quantum mechanical calculations combined with a free energy method, a continuum solvent model, and molecular dynamics simulations to assess an alternative mechanism. Although we are not able to reproduce the experimentally observed DeltaDeltaG++ quantitatively, we present evidence that this DeltaDeltaG++ is very large, in the range found experimentally. We thus conclude that the preferred mechanism may well be different from that in solution, involving an equilibrium pre-protonation of OMP C5 by a catalytic lysine residue that greatly reduces the barrier to subsequent decarboxylation.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0002-7863
pubmed:author
pubmed:issnType
Print
pubmed:day
26
pubmed:volume
123
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
12837-48
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
An alternative explanation for the catalytic proficiency of orotidine 5'-phosphate decarboxylase.
pubmed:affiliation
Accelrys, Inc., 9685 Scranton Road, San Diego, California 92121-3752, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't