Linked Life Data

1287656

Source:http://linkedlifedata.com/resource/pubmed/id/1287656

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
1993-3-16
pubmed:abstractText
Lactate dehydrogenases are of considerable interest as stereospecific catalysts in the chemical preparation of enantiomerically pure alpha-hydroxyacid synthons. For such applications in synthetic organic chemistry it would be desirable to have enzymes which tolerate elevated temperatures for prolonged reaction times, to increase productivity and to extend their applicability to poor substrates. Here, two examples are reported of significant thermostabilizations, induced by site-directed mutagenesis, of an already thermostable protein, the L-lactate dehydrogenase (EC 1.1.1.27, 35 kDa per monomer subunit) from Bacillus stearothermophilus. Thermal inactivation of this enzyme is accompanied by irreversible unfolding of the native protein structure. The replacement of Arg171 by Tyr stabilizes the enzyme against thermal inactivation and unfolding. This stabilizing effect appears to be based on improved interactions between the subunits in the core of the active dimeric or tetrameric forms of the enzyme. The thermal stability of L-lactate dehydrogenase variants with an active site Arg residue, either in the 171 (wild-type) or in the 102 position, is further increased by sulfate ions. The two stabilizing effects are additive, as found for the Arg171Tyr/Gln102Arg double mutant, for which the stability of the protein in 100 mM sulfate solution reaches that of L-lactate dehydrogenases from extreme thermophiles. All mutant proteins retain significant catalytic activity, both in the presence and absence of stabilizing salts, and are viable catalysts in preparative scale reactions.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0269-2139
pubmed:author
pubmed:issnType
Print
pubmed:volume
5
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
769-74
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
Single amino acid substitutions can further increase the stability of a thermophilic L-lactate dehydrogenase.
pubmed:affiliation
Department of Chemistry, University of Toronto, Ontario, Canada.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't