Linked Life Data

3606622

Source:http://linkedlifedata.com/resource/pubmed/id/3606622

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1987-8-27
pubmed:abstractText
A variant of lactate dehydrogenase from Bacillus stearothermophilus has been engineered by site-directed mutagenesis in which an active-site arginine residue at position 171 in the protein sequence is replaced by lysine. Replacement of this arginine by lysine has no effect on co-enzyme binding, a relatively small effect on the rate of turnover of the enzyme, but causes a 2000-fold increase in the Michaelis constant for pyruvate, a 6000-fold increase in the dissociation constant for oxamate and results in a Michaelis constant for lactate which is too high to measure. The decrease in binding energy for these carboxylate-containing substrates caused by this mutation is very large, around 5.5 kcal.mol-1 and in part, is explained by the small increase in the distance of a lysine-substrate carboxylate interaction at this site and the absence of the additional hydrogen bond from a two-point arginine-carboxylate interaction. Consistent with this last observation, the ability of this mutant enzyme to stabilize an NAD+-sulphite compound in its active site (an alternative enzyme-substrate complex which does not involve bifurcated bonding to arginine) is only reduced 14-fold.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0006-291X
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
146
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
346-53
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1987
pubmed:articleTitle
The importance of arginine 171 in substrate binding by Bacillus stearothermophilus lactate dehydrogenase.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't