Linked Life Data

8286367

Source:http://linkedlifedata.com/resource/pubmed/id/8286367

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1994-2-24
pubmed:abstractText
The kinetics and equilibrium properties were investigated for the interconversion between the active dimer of human immunodeficiency virus 1 (HIV-1) protease and its inactive monomeric subunits. The equilibrium dissociation constant (Kd) of the dimeric protease as well as the monomer association rate were obtained by monitoring the fluorescence change of an active-site-directed fluorescent probe (L-737244) upon its binding to the protease. The Kd of the HIV-1 protease is strongly pH dependent. At pH 5.5 where the enzyme is most active catalytically, the extrapolated values of Kd are 0.75 and 3.4 nM at 30 and 37 degrees C, respectively. The rate constant for HIV-1 monomer association, approximately 4 x 10(5) M-1 s-1, is within the range commonly observed for protein-protein interactions. Dimer dissociation was further scrutinized in the presence of an inactive, point mutant form of the enzyme. As a result of subunit exchange between the native and mutant enzymes and the formation of an inactive heterodimer, there was a time-dependent decrease in the activity of the native protease. Enzyme activity could be reinstated with the addition of an active-site-directed inhibitor (L-365862) which selectively binds active dimers. The rate of dimer dissociation was found to also decrease with pH. At pH 5.5 and 30 degrees C, the half-life for subunit dissociation is about 0.5 h. The slow dissociation, coupled with the high stability for dimer association, attests to the importance of allowing sufficient time for dimer-monomer equilibration in kinetic assays in order to avoid reaching erroneous conclusions in studies of dimer dissociation.
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
11
pubmed:volume
33
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
98-105
pubmed:dateRevised
2004-11-17
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Dissociation and association of the HIV-1 protease dimer subunits: equilibria and rates.
pubmed:affiliation
Department of Biological Chemistry, Merck Research Laboratories, West Point, Pennsylvania 19486.
pubmed:publicationType
Journal Article