Linked Life Data

7364050

Source:http://linkedlifedata.com/resource/pubmed/id/7364050

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1980-6-27
pubmed:abstractText
Changes in the [32P]phosphate content of proteins during contraction were investigated with sartorius and semitendinosus muscles dissected from live frogs injected with [32P]orthophosphate. During a single tetanus, the only significant change was the increase in the [32P]phosphate content of the 18,000-dalton light chain of myosin. The extent of light chain phosphorylation was a function of stimulus duration and it amounted maximally to 0.35 mol of [32P]phosphate transferred per mol of light chain. The extent of phosphorylation in stimulated and stretched semitendinosus muscles, which were unable to produce active tension, was nearly identical to that in muscles stimulated at standard rest length, when the time of stimulation was over a half-second. Maximal light chain phosphorylation was also observed in muscles treated with caffein. These results provide evidence for the activation of the light chain kinase in the intact muscle through a process involving Ca2+. The phosphorylation of the light chain associated with tetanic stimulation was reversible. After short tetanuses, dephosphorylation of light chain approximately followed relaxation and after longer tetanuses, dephosphorylation lagged behind relaxation. The role of light chain phosphorylation was investigated in caffeine-treated and untreated muscles by measuring the Ca content of actin and the [32P]phosphate content of light chain. Phosphorylation of light chain protected the actin-bound Ca against removal by EDTA stoichiometrically. It is postulated that the physiological role of light chain phosphorylation is to increase the rate of combination of the cross-bridges with the actin filaments in the contracting phase of the mechanical activity.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0014-9446
pubmed:author
pubmed:issnType
Print
pubmed:volume
39
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1547-51
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1980
pubmed:articleTitle
Myosin light chain phosphorylation during the contraction cycle of frog muscle.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.