Linked Life Data

2543565

Source:http://linkedlifedata.com/resource/pubmed/id/2543565

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1989-7-14
pubmed:abstractText
The allosteric regulation of binding to and the activation of cGMP-dependent protein kinase (cGMP kinase) was studied under identical conditions at 30 degrees C using three forms of cGMP-kinase which differed in the amino-terminal segment, e.g. native cGMP kinase, phosphorylated cGMP kinase which contained 1.4 +/- 0.4 mol phosphate/subunit and constitutively active cGMP kinase which lacked the amino-terminal dimerization domain. These three enzyme forms have identical kinetic constants, e.g. number of cGMP-binding sites, Km values for MgATP and the heptapeptide kemptide, and Vmax values. In the native enzyme, MgATP decreases the affinity for binding site 1. This effect is abolished by 1 M NaCl. In contrast, high concentrations of Kemptide increase the affinity of binding site 2 about fivefold. Under the latter conditions, identical Kd values of 0.2 microM were obtained for sites 1 and 2. Salt, MgATP and Kemptide do not affect the binding kinetics of the phosphorylated or the constitutively active enzyme, suggesting that allosteric regulation depends solely on the presence of a native amino-terminal segment. Cyclic GMP activates the native enzyme at Ka values which are identical with the Kd values for both binding sites. The activation of cGMP-dependent protein kinase is noncooperative but the Ka value depends on the substrate peptide concentration. These results show that the activity of cGMP kinase is primarily regulated by conformational changes within the amino-terminal domain.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0014-2956
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
181
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
643-50
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1989
pubmed:articleTitle
The amino terminus regulates binding to and activation of cGMP-dependent protein kinase.
pubmed:affiliation
Institut für Physiologische Chemie, Medizinische Fakultät, Universität des Saarlandes, Homburg/Saar, Federal Republic of Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't