期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1978
卷号：75
期号：9
页码：4301-4305
DOI：10.1073/pnas.75.9.4301
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：A cyclic AMP-like substance has been isolated from higher plant tissues which can be quantitated with the use of a radioimmunoassay similar to that described by A. L. Steiner, D. M. Kipnis, R. Utiger, and C. Parker [(1969) Proc. Natl. Acad. Sci. USA 64, 367-373]. This compound has been extensively purified and is chromatographically distinct from authentic cyclic AMP. This cyclic AMP-like compound inhibited beef heart 3':5'-cyclic-nucleotide phosphodietsterase (3':5'-cyclic-nucleotide 5'-nucleotidohydrolase, EC 3.1.4.17 ), with half-maximal inhibition occurring at a concentration of 7.6 X 10(-10) M cyclic AMP equivalents. The compound also inhibited cyclic AMP-dependent protein kinase (ATP:protein phosphotransferase; EC 2.7.1.37 ) from bovine heart, with half-maximal inhibition of mixed histone phosphorylation occurring at 8.0 X 10(-11) M cyclic AMP equivalents. Equipotent inhibition of phosphorylation and associated trace ATPase activity were observed with the purified catalytic subunit of cyclic AMP-dependent protein kinase from calf thymus with a synthetic heptapeptide as substrate. Moreover, steady-state kinetic analysis of this inhibition in the latter system showed it to be nonlinear and noncompetitive versus MgATP.
