| Regulatory properties and behavior of activity of carbamoyl phosphate synthetase II (glutamine-hydrolyzing) in normal and proliferating tissues. | |
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MedLine Citation:
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PMID: 7053379 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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In rat livers and hepatomas, carbamoyl phosphate synthetase (glutamine-hydrolyzing) (EC 6.3.5.5) (synthetase II), the rate-limiting enzyme of de novo pyrimidine nucleotide biosynthesis, was separated from carbamoyl phosphate synthetase (ammonia) (EC 6.3.4.16) (synthetase I) ammonium sulfate and hydroxylapatite fractionations and gel filtration on Sephadex G-25. Both liver and hepatoma 3924A synthetase II activities were subject to feedback inhibition by UTP and to stimulation by 5-phosphoribosyl 1-pyrophosphate. UTP (0.5 mM) enhanced the apparent Km for MgATP from 2.3 to 7.6 mM, whereas 0.1 mM 5-phosphoribosyl 1-pyrophosphate reduced it to 0.5 mM. At 2 mM MgATP, 3 or 7 microM 5-phosphoribosyl 1-pyrophosphate yielded half-maximal activation (Ka) in the absence or presence of 0.5 mM UTP; UTP altered the stimulation kinetics from hyperbolic to sigmoidal. In the rat, synthetase II activities were highest in thymus, testis and spleen. In differentiating and regenerating rat livers, activities were 2.2- and 1.5-fold higher than in adult livers. In 17 hepatomas of different growth rates, synthetase II activity increased 1.3- to 9.5-fold over liver values; the rise correlated positively with tumor growth rates. Synthetase II activities also increased in a kidney tumor (5.0-fold) and in a sarcoma (18.1-fold) in the rat and in a human colon tumor (3.3-fold). |
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Authors:
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T Aoki; H P Morris; G Weber |
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Publication Detail:
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Type: Comparative Study; Journal Article; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: The Journal of biological chemistry Volume: 257 ISSN: 0021-9258 ISO Abbreviation: J. Biol. Chem. Publication Date: 1982 Jan |
Date Detail:
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Created Date: 1982-02-25 Completed Date: 1982-02-25 Revised Date: 2007-11-14 |
Medline Journal Info:
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Nlm Unique ID: 2985121R Medline TA: J Biol Chem Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 432-8 Citation Subset: IM |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Carbamoyl-Phosphate Synthase (Glutamine-Hydrolyzing) / isolation & purification, metabolism* Colonic Neoplasms / enzymology Glutamine / pharmacology Humans Hydrogen-Ion Concentration Kidney Neoplasms / enzymology Kinetics Ligases / metabolism* Liver / enzymology* Liver Neoplasms, Experimental / enzymology* Male Neoplasms, Experimental / enzymology Rats Rats, Inbred ACI Ribonucleotides / pharmacology |
| Grant Support | |
ID/Acronym/Agency:
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CA-05034/CA/NCI NIH HHS; CA-10729/CA/NCI NIH HHS; CA-13526/CA/NCI NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Ribonucleotides; 56-85-9/Glutamine; EC 6.-/Ligases; EC 6.3.5.5/Carbamoyl-Phosphate Synthase (Glutamine-Hydrolyzing) |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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