Open AccessEvidence for the Existence of Actomyosin ATPase in the Rat Pancreas
Author(s) -
VANDERMEERS André,
VANDERMEERSPIRET MarieClaire,
HEPBURN Anne,
RATHE Jean,
CHRISTOPHE Jean
Publication year - 1982
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1982.tb05785.x
Subject(s) - myosin , atpase , chemistry , biochemistry , pi , actin , enzyme , electrophoresis , dissociation (chemistry) , pancreas , molecular mass , sodium , nucleoside , gel electrophoresis , specific activity , microbiology and biotechnology , biology , organic chemistry
In a crude extract of rat pancreas, myosin was associated with a protein having the same electrophoretic mobility as actin. This myosin was purified after dissociation of the actomyosin complex with KI‐ATP. On sodium dodecyl‐sulfate/acrylamide gel electrophoresis, the isolated pancreatic myosin showed a major component of approxi‐ mately 200 kDa, and two smaller components with apparent molecular weight of 22 and 15 kDa, respectively. This purified myosin exhibited high ATPase activity in the presence of K + + EDTA or Ca 2+ and very little activity in the presence of Mg 2+ . (K + + EDTA)‐ATPase activity showed one pH optimum at 8.0, while Ca 2+ ‐ATPase activity showed two pH optima at 6.0 and 9.0, respectively. (K + + EDTA)‐stimulated enzyme activity was specific for ATP whereas Ca 2+ ‐stimulated activity showed low specificity for nucleoside triphosphates.