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:6.3.5.5 (
CPS
)
1,262
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Carbamoyl-phosphate synthetase II [
EC 6.3.5.5
] of rat ascites hepatoma cells (AH 13), the first and regulatory enzyme of de novo pyrimidine nucleotide biosynthesis, exists as a multienzyme complex (molecular weight, 870,000) with aspartate carbamoyltransferase [EC 2.1.3.2] and dihydroorotase [EC 3.5.2.3] (Mori, M. & Tatibana, M. (1975) J. Biochem. 78, 239-242). The purified complex was phosphorylated by the catalytic subunit of
cAMP-dependent protein kinase
[EC 2.7.1.37] of rabbit skeletal muscle. The incorporation of 32Pi was 2.2 mol/mol of the complex. The phosphorylation was completely inhibited by the inhibitor protein of the
cAMP-dependent protein kinase
. Among the substrates and effectors of the enzyme complex tested, only MgUTP, an allosteric inhibitor of
carbamoyl-phosphate synthetase
II, strongly inhibited the phosphorylation; this inhibition was due probably to the competition of MgUTP with y inhibited by the inhibitor protein of the
cAMP-dependent protein kinase
. Among the substrates and effectors of the enzyme complex tested, only MgUTP, an allosteric inhibitor of
carbamoyl-phosphate synthetase
II, strongly inhibited the phosphorylation; this inhibition was due probably to the competition of MgUTP with y inhibited by the inhibitor protein of the
cAMP-dependent protein kinase
. Among the substrates and effectors of the enzyme complex tested, only MgUTP, an allosteric inhibitor of
carbamoyl-phosphate synthetase
II, strongly inhibited the phosphorylation; this inhibition was due probably to the competition of MgUTP with the substrate MgATP for the protein kinase. The complex that was phosphorylated by
cAMP-dependent protein kinase
was dephosphorylated by phosphoprotein phosphatase [EC 3.1.3.16] of rat skeletal muscle. The complex was also phosphorylated by cAMP-independent protein kinase activity present in the extract of AH 13 cells and dephosphorylated by phosphoprotein phosphatase activity of the same origin. These results suggest that the complex is subject to phosphorylation and dephosphorylation in the living cells. Phosphorylation of the complex by
cAMP-dependent protein kinase
was associated only with a slight change, albeit definite, in the activity of
carbamoyl-phosphate synthetase
II under the assay conditions. Thus, the physiological significance of phosphorylation-dephosphorylation remains to be further studied.
...
PMID:Phosphorylation and dephosphorylation of carbamoyl-phosphate synthetase II complex of rat ascites hepatoma cells. 611 55
