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The effect of the nitrosourea analog of thymidine, 3'-[3-(2-chloroethyl)-3-nitrosoureido]-3'-deoxythymidine, on Escherichia coli thymidine kinase.
- Source :
-
Biochimica et biophysica acta [Biochim Biophys Acta] 1980 Nov 06; Vol. 616 (1), pp. 35-40. - Publication Year :
- 1980
-
Abstract
- Escherichia coli thymidine kinase (ATP:thymidine 5'-phosphotransferase, EC 2.7.1.21) is irreversibly inactivated by incubation with 3'-[3-(2-chloroethyl)-3-nitrosoureido]-3'-deoxythymidine (3'-CTNU). The inactivation of the enzyme followed first-order kinetics even after loss of 96% of the original activity. This indicates that the inactivation process is a one-kill phenomenon and not a generation of less active enzyme. The addition of a preincubated aqueous solution of 3'-CTNU to the enzyme reaction mixture did not inactivate the enzyme. ATP . Mg2+ but not thymidine protects the enzyme from inactivation by 3'-CTNU. The allosteric regulators, dTTP, dCTP and dCDP also afforded complete protection of the enzyme from inactivation by 3'-CTNU. These data indicate that the dimer form of the enzyme is completely resistant to inactivation by 3'-CTNU, but the monomer form of the enzyme is sensitive. The specificity of the protection is supported by the finding that neither ATP . Mg2+ nor thymidine protect yeast alcohol dehydrogenase from inactivation by this nitrosourea analog of thymidine.
- Subjects :
- Adenosine Triphosphate pharmacology
Allosteric Regulation
Magnesium pharmacology
Thymidine pharmacology
Antineoplastic Agents pharmacology
Dideoxynucleosides
Escherichia coli enzymology
Nitrosourea Compounds pharmacology
Thymidine analogs & derivatives
Thymidine Kinase antagonists & inhibitors
Subjects
Details
- Language :
- English
- ISSN :
- 0006-3002
- Volume :
- 616
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Biochimica et biophysica acta
- Publication Type :
- Academic Journal
- Accession number :
- 7002216
- Full Text :
- https://doi.org/10.1016/0005-2744(80)90261-2