Repair of DNA treated with. gamma. -irradiation and chemical carcinogens. Progress report, June 1, 1975--January 31, 1976. [MMS, methylnitrosourea, 7-bromomethyl-12-methylbenz(a)-anthracene, Escherichia coli]
Enzymatic mechanisms of DNA repair are under investigation. From E. coli an endonuclease active on apurinic acid has been separated from endonuclease II active on DNA treated with methylmethane sulfonate, methylnitrosourea, 7-bromomethyl-12-methylbenz(a)anthracene and ..gamma..-irradiation. Mutants have been identified for each enzyme. The purification of both enzymes is proceeding and the mechanism of action of endonuclease II which has both an N-glycosidase and a phosphodiester hydrolase activity is under investigation. Evidence demonstrating exonuclease III is an enzyme separate from the apurinic acid endonuclease and endonuclease II has been accumulated but this is still under investigation. Work has been completed on 7-bromomethyl-12-methylbenz(a)anthracene treated DNA as a substrate and is being continued on the inhibitory effects of phorbol ester on endonuclease II. Finally, the properties of an enzyme from calf liver active on depurinated DNA have been compared with those of a comparable enzyme from calf thymus. Evidence that they are isozymes has been found.
- Research Organization:
- Case Western Reserve Univ., Cleveland, Ohio (USA). Dept. of Biochemistry
- OSTI ID:
- 7352717
- Report Number(s):
- COO-2725-1
- Country of Publication:
- United States
- Language:
- English
Similar Records
Repair of DNA treated with. gamma. -irradiation and chemical carcinogens. Progress report, February 1, 1976--February 28, 1977. [Endonuclease reactions in E. coli]
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Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ALKANES
AMIDES
AROMATICS
BACTERIA
BENZANTHRACENE
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
CARBONIC ACID DERIVATIVES
CARCINOGENS
CONDENSED AROMATICS
CRYOGENIC FLUIDS
DNA
ELECTROMAGNETIC RADIATION
ENZYMES
ESCHERICHIA COLI
ESTERS
FLUIDS
GAMMA RADIATION
HYDROCARBONS
IONIZING RADIATIONS
METHANE
MICROORGANISMS
NITROSO COMPOUNDS
NUCLEASES
NUCLEIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PHOSPHOTRANSFERASES
RADIATION EFFECTS
RADIATIONS
RECOVERY
REPAIR
SULFONIC ACID ESTERS
TRANSFERASES
UREA