Linked Life Data

2148671

Source:http://linkedlifedata.com/resource/pubmed/id/2148671

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1991-2-19
pubmed:abstractText
A cross-linked form of yeast phosphofructokinase in which up to four of the subunits of the octameric molecule were found covalently linked by dimethyl suberimidate exhibits no cooperativity with respect to fructose 6-phosphate and is only weakly inhibited by ATP. The modified enzyme is activated by AMP and fructose 2,6-bisphosphate. Both effectors abolish ATP inhibition even at low concentration of fructose 6-phosphate and increase the affinity of modified phosphofructokinase to fructose 6-phosphate but are without significant effect on the respective maximum activity. The corresponding kinetic patterns exhibit similarity to those of the native enzyme at high concentration of fructose 6-phosphate. In comparison to native phosphofructo-kinase the extent of activation by AMP and fructose 2,6-bisphosphate is of minor amount. As shown for native phosphofructokinase, the enzyme which had been cross-linked in the absence of any effector shows a lag phase of product formation. This initial transient phase completely disappears if the enzyme is modified in the presence of fructose 6-phosphate, fructose 1,6-bisphosphate, and fructose 2,6-bisphosphate, respectively. The same result is obtained by preincubation of the enzyme cross-linked in the absence of any effector with each of these fructose phosphates. The kinetic properties of the modified enzyme indicate that cooperativity with respect to fructose 6-phosphate is not a prerequisite for the allosteric modulation of enzyme activity by AMP and fructose 2,6-bisphosphate and support the idea of multiple conformational determinants in yeast phosphofructokinase. The results suggest that moderate intramolecular cross-linking can provide a simple experimental tool to stabilize different conformational states of an enzyme.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0232-766X
pubmed:author
pubmed:issnType
Print
pubmed:volume
49
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
317-25
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
Yeast phosphofructokinase: pre-steady-state and stationary kinetic studies on a cross-linked enzyme form.
pubmed:affiliation
Institut für Biochemie, Karl-Marx-Universität Leipzig, DDR.
pubmed:publicationType
Journal Article, Comparative Study