Linked Life Data

6226665

Source:http://linkedlifedata.com/resource/pubmed/id/6226665

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
21
pubmed:dateCreated
1983-12-17
pubmed:abstractText
In order to understand the effect of phosphorylation on phosphofructokinase, the allosteric kinetic behavior, ligand binding at various pHs, and pH-dependent cold inactivation of phosphofructokinase phosphorylated to different extents were studied. A subtilisin-digested phosphofructokinase from which a COOH-terminal peptide containing a phosphorylation site has been cleaved (Riquelme, P. T., and Kemp, R. G. (1980) J. Biol. Chem. 255, 4367-4371) was also included in these studies in order to investigate the possible role of this region of the molecule. Allosteric kinetics and direct binding experiments have shown that increasing phosphorylation of phosphofructokinase results in increased sensitivity to ATP inhibition and stronger binding of ATP to the inhibitory site of the enzyme. Ths subtilisin-cleaved phosphofructokinase is the least sensitive to the inhibition and shows the weakest binding of ATP. The opposite effect is observed with the binding isotherms of fructose-6-P. There is no difference in the binding of fructose-2,6-P2 among these enzymes. Binding of ATP to the inhibitory site of these enzymes as determined by fluorescence quenching (Pettigrew, D. W., and Frieden, C. (1979) J. Biol. Chem. 254, 1887-1895) is affected by pH; the binding is greatly enhanced at lower pH. Moreover, there is little difference in the binding among the modified enzymes at pH 8, but at lower pHs the binding to the phosphorylated enzyme is much more enhanced than the dephosphoenzyme. A pH-dependent cold inactivation study has shown that the phosphorylation of the enzyme causes an increase in the pK value for the inactivation, and the extent of the pK shift depends upon the degree of phosphorylation. Based on these results, a model originally proposed by Frieden et al. (Frieden, C., Gilbert, H. R., and Bock, P. E. (1976) J. Biol. Chem. 251, 5644-5647) can be applied to explain a possible role for the phosphorylation and the peptide portion of phosphofructokinase in its complex allosteric kinetic behavior.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
10
pubmed:volume
258
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
13292-8
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1983
pubmed:articleTitle
Significance of phosphorylation of phosphofructokinase.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.