Repair of DNA treated with. gamma. -irradiation and chemical carcinogens. Progress report, February 1, 1976--February 28, 1977. [Endonuclease reactions in E. coli]
Enzymes from E. coli which recognize damage in DNA due to chemical carcinogens and ..gamma..-irradiation are under study. Endonuclease II, which recognizes DNA treated with methylmethane sulfonate, methylnitrosourea, 7-bromomethyl-12-methylbenz(a)anthracene and ..gamma..-irradiation. Apurinic endonuclease (endonuclease VI) recognizes apurinic and apyrimidinic acid sites. These enzymes have now been purified to homogeneity and separated from exonuclease III which other groups have thought to be identical with one or both of the endonucleases. A series of mutants of E. coli were found to lack one, two, or all of these enzymes. The genetic loci for the two endonucleases are very close to the Exonuclease III locus at 38.2 minutes. An attempt to relate in vivo sensitivity to MMS to lack of specific enzymes has been made. Substrates for endonuclease II have been examined. ..beta..-propiolactone treated DNA has been found to be substrate and details of this are being examined. The nature of the lesion in ..gamma..-irradiated DNA is under investigation. A search for mammalian enzymes which are N-glycosidases is underway.
- Research Organization:
- Case Western Reserve Univ., Cleveland, Ohio (USA). Dept. of Biochemistry
- DOE Contract Number:
- EY-76-S-02-2725
- OSTI ID:
- 7294601
- Report Number(s):
- COO/2725-2
- Country of Publication:
- United States
- Language:
- English
Similar Records
Endonuclease II, apurinic acid endonuclease, and exonuclease III
Repair of DNA treated with. gamma. -irradiation and chemical carcinogens. Comprehensive report of entire period of ERDA support from June 1, 1975--January 15, 1978
Related Subjects
550400* -- Genetics
560112 -- Radiation Effects on Biochemicals-- In Microorganisms-- (-1987)
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BACTERIA
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BIOLOGICAL RECOVERY
CARCINOGENS
CHEMICAL RADIATION EFFECTS
CHEMISTRY
DNA
ELECTROMAGNETIC RADIATION
ENZYMES
ESCHERICHIA COLI
GAMMA RADIATION
IONIZING RADIATIONS
KINETICS
MICROORGANISMS
NUCLEIC ACIDS
ORGANIC COMPOUNDS
RADIATION CHEMISTRY
RADIATION EFFECTS
RADIATIONS
REACTION KINETICS