Cyclic GMP-dependent protein kinase and smooth muscle relaxation.
Cyclic guanosine monophosphate (cGMP)-dependent protein kinase has been cloned from bovine trachea. The isozymes I alpha and I beta, which differ only in their amino-terminal domains were expressed transiently in COS-7 cells. Both isozymes were activated by cGMP and cyclic adenosine monophosphate (cAMP). However, approximately 10-fold higher concentrations of cyclic nucleotides were needed to activate the I beta enzyme than the I alpha enzyme. The KA values for cAMP were 9.1 and greater than 20 microM for the I alpha and I beta isozymes, respectively. It is therefore unlikely that an unmodified I beta enzyme that occurs in high concentrations in vascular smooth muscle can be activated in vivo by cAMP.
Landgraf
W
W
Institut für Pharmakologie und Toxikologie, Technischen Universität München, Germany.
Ruth
P
P
Keilbach
A
A
May
B
B
Welling
A
A
Hofmann
F
F
D000818:Animals; D002417:Cattle; D002460:Cell Line; D003001:Cloning, Molecular; D000242:Cyclic AMP / Q000494:pharmacology; D006152:Cyclic GMP / Q000494:pharmacology*; D007527:Isoenzymes / Q000737:chemistry / Q000378:metabolism; D009126:Muscle Relaxation; D009131:Muscle, Smooth, Vascular / Q000201:enzymology / Q000502:physiology*; D010957:Plasmids; D011494:Protein Kinases / Q000737:chemistry / Q000378:metabolism*; D014162:Transfection
D007527:Isoenzymes; D000242:Cyclic AMP; D011494:Protein Kinases; D006152:Cyclic GMP