Linked Life Data

7490260

Source:http://linkedlifedata.com/resource/pubmed/id/7490260

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1996-1-2
pubmed:abstractText
Phosphoenolpyruvate carboxylase (PEPC) [EC 4.1.1.31] has a highly conserved and unique sequence, 578-FHGRGGSIGRGGAP-591 (on Escherichia coli, PEPC), in which a GRGG motif is repeated twice with two intervening residues. Since previous chemical modification studies suggested the functional importance of arginine residues, the invariant Arg587 in this region was replaced with Ser, and the enzymatic properties of the resulting mutant enzyme (R587S) were investigated. Replacement led to virtual loss of the catalytic activity to form oxaloacetate. The specific activity was 37 nmol.min-1.mg-1, which corresponds to 2 x 10(-4)-fold the activity of the wild-type enzyme. However, the activity of bicarbonate- and Mg(2+)-dependent hydrolysis of phosphoenolpyruvate (PEP) to pyruvate appeared for the mutant enzyme with a specific activity of 2.1 mumol.min-1.mg-1. In view of the stepwise reaction mechanism proposed for PEPC, this activity can be attributed to impairment of the subsequent partial reaction(s) following the formation of the intermediate carboxyphosphate. The half-saturation concentration (S0.5) of HCO3- in R587S was about 100-fold that in the wild-type enzyme, whereas the respective values for PEP and Mg2+ were 20- and 15-fold, indicative of this residue participating in the binding of HCO3-.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0021-924X
pubmed:author
pubmed:issnType
Print
pubmed:volume
117
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1196-200
pubmed:dateRevised
2007-12-19
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Catalytic role of an arginine residue in the highly conserved and unique sequence of phosphoenolpyruvate carboxylase.
pubmed:affiliation
Faculty of Science, Kyoto University.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't