Linked Life Data

11050223

Source:http://linkedlifedata.com/resource/pubmed/id/11050223

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
22
pubmed:dateCreated
2000-11-28
pubmed:abstractText
The idea that enzymes accelerate their reactions by entropic effects has played a major role in many prominent proposals about the origin of enzyme catalysis. This idea implies that the binding to an enzyme active site freezes the motion of the reacting fragments and eliminates their entropic contributions, (delta S(cat)(double dagger))', to the activation energy. It is also implied that the binding entropy is equal to the activation entropy, (delta S(w)(double dagger))', of the corresponding solution reaction. It is, however, difficult to examine this idea by experimental approaches. The present paper defines the entropic proposal in a rigorous way and develops a computer simulation approach that determines (delta S(double dagger))'. This approach allows us to evaluate the differences between (delta S(double dagger))' of an enzymatic reaction and of the corresponding reference reaction in solution. Our approach is used in a study of the entropic contribution to the catalytic reaction of subtilisin. It is found that this contribution is much smaller than previously thought. This result is due to the following: (i) Many of the motions that are free in the reactants state of the reference solution reaction are also free at the transition state. (ii) The binding to the enzyme does not completely freeze the motion of the reacting fragments so that (delta S(double dagger))' in the enzymes is not zero. (iii) The binding entropy is not necessarily equal to (delta S(w)(double dagger))'.
pubmed:grant
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0027-8424
pubmed:author
pubmed:issnType
Print
pubmed:day
24
pubmed:volume
97
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
11899-904
pubmed:dateRevised
2009-11-18
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
How important are entropic contributions to enzyme catalysis?
pubmed:affiliation
Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't