Linked Life Data

3778867

Source:http://linkedlifedata.com/resource/pubmed/id/3778867

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
19
pubmed:dateCreated
1987-1-9
pubmed:abstractText
Coenzyme analogues with the adenosine ribose replaced with n-propyl, n-butyl, and n-pentyl groups; coenzyme analogues with the adenosine replaced with 3-(4-acetylanilino)propyl and 6-(4-acetylanilino)hexyl moieties; and nicotinamide mononucleotide, nicotinamide hypoxanthine dinucleotide, and 3-acetylpyridine adenine dinucleotide were used in steady-state kinetic studies with native and activated, amidinated enzymes. The Michaelis and inhibition constants increased up to 100-fold upon modification of coenzyme or enzyme. Turnover numbers with NAD+ and ethanol increased in some cases up to 10-fold due to increased rates of dissociation of enzyme-reduced coenzyme complexes. Rates of dissociation of oxidized coenzyme appeared to be mostly unaffected, but the values calculated (10-60 s-1) were significantly less than the turnover numbers with acetaldehyde and reduced coenzyme (20-900 s-1, at pH 8, 25 degrees C). Rates of association of coenzyme analogues also decreased up to 100-fold. When Lys-228 in the adenosine binding site was picolinimidylated, turnover numbers increased about 10-fold with NAD(H). Furthermore, the pH dependencies for association and dissociation of NAD+ and turnover number with NAD+ and ethanol showed the fastest rates above a pK value of 8.0. Turnover with NADH and acetaldehyde was fastest below a pK value of 8.1. These results can be explained by a mechanism in which isomerization of the enzyme-NAD+ complex (110 s-1) is partially rate limiting in turnover with NAD+ and ethanol (60 s-1) and is controlled by ionization of the hydrogen-bonded system that includes the water ligated to the catalytic zinc and the imidazole group of His-51.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
23
pubmed:volume
25
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
5396-402
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1986
pubmed:articleTitle
Kinetics of native and modified liver alcohol dehydrogenase with coenzyme analogues: isomerization of enzyme-nicotinamide adenine dinucleotide complex.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.