TY - JOUR
T1 - Calmodulin-dependent protein kinases purified from rat brain and rabbit liver
AU - Schworer, Charles M.
AU - McClure, Robert W.
AU - Soderling, Thomas R.
N1 - Funding Information:
i Supported in part by NIH Grant AM17808. a Supported by Vanderbilt Diabetes Research and Training Center Grant 5T35AM07383. a To whom correspondence should be addressed. 4 Abbreviations used: EGTA, ethylene glycol his@-aminoethyl ether)-N,N’-tetraacetic acid; Hepes, 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid; CaM, calmodulin.
PY - 1985/10
Y1 - 1985/10
N2 - A calmodulin-dependent protein kinase was purified from rat brain by the same protocol used previously for a rabbit liver calmodulin-dependent glycogen synthase kinase. The rat brain kinase readily phosphorylated rabbit skeletal muscle glycogen synthase at sites 1b and 2, the same sites phosphorylated by rabbit liver calmodulin-dependent kinase. The two kinases have other similarities: substrate specificity, potent inhibition by sodium fluoride, and nearly equal Ka's (10-20 nm) for calmodulin. Also, both enzymes have similar Stokes radii, 70 Å (rabbit liver) and 75 Å (rat brain), but quite different sedimentation coefficients, 10.6 S and 17.4 S, respectively. Consequently, the calculated molecular weights are also different: 560,000 for the brain enzyme and 300,000 for the liver enzyme. The major subunit of the rat brain kinase appears to be a single 51-kDa peptide, not a doublet pattern of 51- and 53-kDa subunits that is characteristic of the rabbit liver enzyme. Our findings are consistent with the hypothesis that the rat brain and rabbit liver enzymes belong to a class of closely related calmodulin-dependent protein kinases, possibly isozymes. This class of enzymes may be responsible for regulating several of the known calcium-dependent physiological functions.
AB - A calmodulin-dependent protein kinase was purified from rat brain by the same protocol used previously for a rabbit liver calmodulin-dependent glycogen synthase kinase. The rat brain kinase readily phosphorylated rabbit skeletal muscle glycogen synthase at sites 1b and 2, the same sites phosphorylated by rabbit liver calmodulin-dependent kinase. The two kinases have other similarities: substrate specificity, potent inhibition by sodium fluoride, and nearly equal Ka's (10-20 nm) for calmodulin. Also, both enzymes have similar Stokes radii, 70 Å (rabbit liver) and 75 Å (rat brain), but quite different sedimentation coefficients, 10.6 S and 17.4 S, respectively. Consequently, the calculated molecular weights are also different: 560,000 for the brain enzyme and 300,000 for the liver enzyme. The major subunit of the rat brain kinase appears to be a single 51-kDa peptide, not a doublet pattern of 51- and 53-kDa subunits that is characteristic of the rabbit liver enzyme. Our findings are consistent with the hypothesis that the rat brain and rabbit liver enzymes belong to a class of closely related calmodulin-dependent protein kinases, possibly isozymes. This class of enzymes may be responsible for regulating several of the known calcium-dependent physiological functions.
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U2 - 10.1016/0003-9861(85)90487-4
DO - 10.1016/0003-9861(85)90487-4
M3 - Article
C2 - 3931554
AN - SCOPUS:0022402695
SN - 0003-9861
VL - 242
SP - 137
EP - 145
JO - Archives of Biochemistry and Biophysics
JF - Archives of Biochemistry and Biophysics
IS - 1
ER -