Linked Life Data

2140055

Source:http://linkedlifedata.com/resource/pubmed/id/2140055

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1990-6-20
pubmed:abstractText
A system composed of toluene, phospholipids, and Triton X-100 in which the ATPase activity of bovine heart submitochondrial particles can be studied at low water concentrations and high temperatures is described. In this system, ATPase activity starts to appear at 0.5% (v/v) water and increases as the concentration of water is increased. At 3.8% water, the enzyme exhibits saturation kinetics with respect to Mg-ATP with a Km similar to that observed in an all-water system (approximately 300 microM), but the Vmax is about 100 times lower (6 nmol min-1 mg-1) than that in water. At concentrations of water between 0.5% and 2%, the enzyme catalyzes ATP hydrolysis at temperatures of up to 91 degrees C. The conditions for achieving catalysis at high temperatures are described. Even though at low water concentrations the enzyme catalyzes ATP hydrolysis at temperatures significantly higher than in totally aqueous media, the optimal temperature for hydrolysis (approximately 58 degrees C) is independent of the water content. The half-life of the enzyme at high temperatures is significantly higher at low water concentrations than in aqueous media. In the system described, the enzyme is located in a compartment distinct from that of the substrate and products of the reaction. Apparently, the enhancement of catalytic rates by water is due to a higher conformational mobility of the protein; the same factor causes a decrease in the thermostability of the enzyme.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
23
pubmed:volume
29
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
751-7
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
Enzyme catalysis in organic solvents with low water content at high temperatures. The adenosinetriphosphatase of submitochondrial particles.
pubmed:affiliation
Departamento de Bioquímica, Centro de Investigación y Estudios Avanzados, México.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't