Linked Life Data

3199

Source:http://linkedlifedata.com/resource/pubmed/id/3199

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1976-6-2
pubmed:abstractText
Ribulose-1,5-bisphosphate carboxylase was activated by incubation with CO2 and Mg2++, and inactivated upon removal of CO2 and Mg2+ by gel filtration. The activation process involved CO2 rather than HCO3-. The activity of the enzyme was dependent upon the preincubation concentrations of CO2 and Mg2+ and upon the preincubation pH, indicating that activation involved the reversible formation of an equilibrium complex of enzyme-CO2-Mg. The initial rate of activation was linearly dependent upon the CO2 concentration but independent of the Mg2+ concentration. Kinetic analyses indicated that the enzyme reacted first with CO2 in a rate-determining and reversible step, followed by a rapid reaction with Mg2+ to form an active ternary complex (see eq 1 in text). The pseudo-first order rate constant, kobsd, for the activation process at constant pH was derived: kobsd=k1[CO2] + (k2k4/k3[Mg2+]). Experimentally, kobsd was shown to be linearly dependent upon the CO2 concentration and inversely dependent upon the Mg2+ concentration. The activity of the enzyme after preincubation to equilibrium at constant concentrations of CO2 and Mg2+ increased as the preincubation pH was raised, indicating that CO2 reacted with an enzyme group whose pK was distinctly alkaline. It is proposed that the activation of ribulose-1, 5-biphosphate carboxylane involves the formation of a carbamate.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
10
pubmed:volume
15
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
529-36
pubmed:dateRevised
2009-10-27
pubmed:meshHeading
pubmed:year
1976
pubmed:articleTitle
The activation of ribulose-1,5-bisphosphate carboxylase by carbon dioxide and magnesium ions. Equilibria, kinetics, a suggested mechanism, and physiological implications.
pubmed:publicationType
Journal Article