TY - JOUR
T1 - Studies on functional domains of the regulatory subunit of bovine heart adenosine 3':5'-monophosphate-dependent protein kinase.
AU - Flockhart, D. A.
AU - Watterson, D. M.
AU - Corbin, J. D.
N1 - Copyright:
Medline is the source for the citation and abstract of this record.
PY - 1980/5/25
Y1 - 1980/5/25
N2 - The functional domains of the regulatory subunit of isozyme II of cAMP-dependent protein kinase were studied. It was shown using Edman degradation that the regulatory subunit contained a phosphorylated residue which was very close in primary sequence to the site most sensitive to hydrolysis by low trypsin concentrations as postulated previously (Corbin, J.D., Sugden, P.H., West, L., Flockhart, D.A., Lincoln, T.M., and McCarthy, D. (1978) J. Biol. Chem. 253, 3997-4003). Catalytic subunit incorporated 0.9 mol of 32P from [gamma-32P]ATP into a preparation of regulatory subunit that contained 1.1 mol of endogenous phosphate. After phosphorylation by the catalytic subunit, the regulatory subunit contained 2.2 mol of chemical phosphate. The effects of heat denaturation upon the rate and extent of phosphorylation of the regulatory subunit were compared with the effects of these treatments upon the cAMP binding and inhibitory domains. These data suggested that the regulatory subunit required factors in addition to an intact phosphorylatable primary sequence in order for inhibitory activity to be expressed. Such factors might be part of the secondary or tertiary structure of the protein. These studies are discussed with respect to the mechanism of inhibition of catalytic activity, and a model of the regulatory subunit structure is proposed.
AB - The functional domains of the regulatory subunit of isozyme II of cAMP-dependent protein kinase were studied. It was shown using Edman degradation that the regulatory subunit contained a phosphorylated residue which was very close in primary sequence to the site most sensitive to hydrolysis by low trypsin concentrations as postulated previously (Corbin, J.D., Sugden, P.H., West, L., Flockhart, D.A., Lincoln, T.M., and McCarthy, D. (1978) J. Biol. Chem. 253, 3997-4003). Catalytic subunit incorporated 0.9 mol of 32P from [gamma-32P]ATP into a preparation of regulatory subunit that contained 1.1 mol of endogenous phosphate. After phosphorylation by the catalytic subunit, the regulatory subunit contained 2.2 mol of chemical phosphate. The effects of heat denaturation upon the rate and extent of phosphorylation of the regulatory subunit were compared with the effects of these treatments upon the cAMP binding and inhibitory domains. These data suggested that the regulatory subunit required factors in addition to an intact phosphorylatable primary sequence in order for inhibitory activity to be expressed. Such factors might be part of the secondary or tertiary structure of the protein. These studies are discussed with respect to the mechanism of inhibition of catalytic activity, and a model of the regulatory subunit structure is proposed.
UR - http://www.scopus.com/inward/record.url?scp=0019332528&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0019332528&partnerID=8YFLogxK
U2 - 10.1016/s0021-9258(19)85509-6
DO - 10.1016/s0021-9258(19)85509-6
M3 - Article
C2 - 6246071
AN - SCOPUS:0019332528
SN - 0021-9258
VL - 255
SP - 4435
EP - 4440
JO - The Journal of biological chemistry
JF - The Journal of biological chemistry
IS - 10
ER -