Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: EC:4.1.1.17 (
ornithine decarboxylase
)
6,351
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
In Y1 adrenocortical tumor cells, corticotropin (ACTH), cyclic AMP, and 8-bromoadenosine 3',5'-monophosphate (8BrcAMP) stimulated
ornithine decarboxylase
activity (
L-ornithine carboxy-lyase
,
EC 4.1.1.17
) and steroidogenesis. The concentrations required for half-maximal activation of
ornithine decarboxylase
were 60 pM for ACTH and 1 mM for 8BrcAMP; the concentrations required for half-maximal activation of steroidogenesis were 50 pM for ACTH and 0.2 mM for 8BrcAMP.
Ornithine decarboxylase
activity increased 1.5 hr after the addition of these agents, reached a maximum between 4 and 6 hr, and then declined. Mutant clones with impaired ACTH-responsive adenylate cyclase systems [
ATP pyrophosphate-lyase
(cyclizing), EC 4.6.1.1]did not respond to ACTH with increased
ornithine decarboxylase
activity, but they responded normally to added cyclic AMP. These results indicate that adenylate cyclase and cyclic AMP are necessary for the stimulation of
ornithine decarboxylase
activity by ACTH. In a series of Y1(Kin) mutants with altered cyclic AMP-dependent protein kinase activities (ATP:protein phosphotransferase, EC 2.7.1.37), the effects of ACTH on
ornithine decarboxylase
also were attenuated. These findings suggest that cyclic AMP-dependent protein kinase also plays a necessary role in the stimulation of
ornithine decarboxylase
activity by ACTH. The effects of ACTH on
ornithine decarboxylase
in the Kin mutants, however, were quantitatively different from the effects on steroidogenesis and did not closely reflect the degree of defect in cyclic AMP-dependent protein kinase activity. These differences suggest that the pathways of ACTH action leading to stimulation of steroidogenesis and
ornithine decarboxylase
activity diverge subsequent to activation of the protein kinase.
...
PMID:Regulation of ornithine decarboxylase activity by corticotropin in adrenocortical tumor cell clones: roles of cyclic AMP and cyclic AMP-dependent protein kinase. 624 65
