Linked Life Data

10360944

Source:http://linkedlifedata.com/resource/pubmed/id/10360944

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
23
pubmed:dateCreated
1999-7-2
pubmed:abstractText
High pressure causes biphasic effects on the oxidation of benzyl alcohol by yeast alcohol dehydrogenase as expressed in the kinetic parameter V/K which measures substrate capture. Moderate pressure increases the rate of capture of benzyl alcohol by activating the hydride transfer step. This means that the transition state for hydride transfer has a smaller volume than the free alcohol plus the capturing form of enzyme, with a DeltaV of -39 +/- 1 mL/mol, a value that is relatively large. This is the first physical property of an enzymatic transition state thus characterized, and it offers new possibilities for structure-activity analyses. Pressures of >1.5 kbar decrease the rate of capture of benzyl alcohol by favoring a conformation of the enzyme which binds nicotinamide adenine dinucleotide (NAD+) less tightly. This means that the ground state for tight binding, E-NAD+, has a larger volume than the collision complex, E-NAD+, with a DeltaV of 73 +/- 2 mL/mol. The equilibrium constant of the conformational change Keq is 75 +/- 13 at 1 atm. The effects of pressure on the capture of NAD+ have no activation phase because the conformational change is now being expressed kinetically instead of thermodynamically, together with but in opposition to hydride transfer, causing the effects to cancel. For yeast alcohol dehydrogenase, this conformational change had not been detected previously, but similar conformational changes have been found by spectroscopic means in other dehydrogenases, and some of them are also sensitive to pressure. The opposite signs for the volume change of tighter binding and hydride transfer run contrary to Pauling's hypothesis that substrates are bound more tightly in the transition state than in the Michaelian reactant state.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
8
pubmed:volume
38
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
7470-5
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Effects of pressure on the kinetics of capture by yeast alcohol dehydrogenase.
pubmed:affiliation
Department of Biochemistry, Changwon National University, Changwon City, Kyungnam, South Korea.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.