Does oxygen enhance the radiation-induced inactivation of penicillinase
Journal Article
·
· Radiat. Res.; (United States)
The radiation-induced inactivation of penicillinase (..beta..-lactamase, EC 3.5.2.6) in dilute aqueous solutions buffered with phosphate was studied by examining enzyme radiosensitivity in the presence of various gases (He, O/sub 2/, H/sub 2/, N/sub 2/O and N/sub 2/O + O/sub 2/). The introduction of either N/sub 2/O or O/sub 2/ was found to reduce the radiodamage. On the other hand, H/sub 2/ or N/sub 2/O + O/sub 2/ gas mixture enhanced the radiosensitivity. In the presence of formate and oxygen no enzyme inactivation was detected. The results indicated that the specific damaging efficiency of H atoms is more than twofold higher than that of OH radicals; therefore, in 50 mM phosphate buffer, where more than half the free radicals are H atoms, the H radicals are responsible for the majority of the damage. The superoxide radicals appeared to be completely inactive and did not contribute to enzyme inactivation. Oxygen affected the radiosensitivity in two ways: (1) it protected by converting e/sub aq//sup -/ and H into harmless O/sub 2/-radicals; and (2) it increased inactivation by enhancing the damage brought about by OH radicals (OER = 2.6). In oxygenated buffer the protection effect of oxygen exceeded that of sensitization, thus giving rise to a moderate overall protection effect.
- Research Organization:
- Hebrew Univ., Jerusalem, Israel
- OSTI ID:
- 5099910
- Journal Information:
- Radiat. Res.; (United States), Journal Name: Radiat. Res.; (United States) Vol. 82:1; ISSN RAREA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Does oxygen enhance the radiation-induced inactivation of penicillinase. Progress report, December 1, 1979-November 30, 1980
Radiation-induced damage in E. coli B: The effect of superoxide radicals and molecular oxygen. Progress report, December 1, 1978--November 30, 1979
Radiation-induced damage in Escherichia coli B: the effect of superoxide radicals and molecular oxygen. [. gamma. irradiation of bacterial suspensions]
Technical Report
·
Mon Dec 31 23:00:00 EST 1979
·
OSTI ID:5414499
Radiation-induced damage in E. coli B: The effect of superoxide radicals and molecular oxygen. Progress report, December 1, 1978--November 30, 1979
Technical Report
·
Wed Oct 31 23:00:00 EST 1979
·
OSTI ID:5932727
Radiation-induced damage in Escherichia coli B: the effect of superoxide radicals and molecular oxygen. [. gamma. irradiation of bacterial suspensions]
Journal Article
·
Thu Nov 30 23:00:00 EST 1978
· Radiat. Res.; (United States)
·
OSTI ID:6381743
Related Subjects
550200 -- Biochemistry
560111* -- Radiation Effects on Biochemicals-- In Vitro-- (-1987)
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ALKALI METAL ISOTOPES
ANTIBIOTICS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
CESIUM 137
CESIUM ISOTOPES
CHALCOGENIDES
CHEMICAL RADIATION EFFECTS
CHEMISTRY
DATA
DOSE-RESPONSE RELATIONSHIPS
DRUGS
ELECTROMAGNETIC RADIATION
ELEMENTS
ENZYME INHIBITORS
EXPERIMENTAL DATA
GAMMA RADIATION
HYDROGEN
INACTIVATION
INFORMATION
IONIZING RADIATIONS
ISOTOPES
KINETICS
NITROGEN COMPOUNDS
NITROGEN OXIDES
NITROUS OXIDE
NONMETALS
NUCLEI
NUMERICAL DATA
ODD-EVEN NUCLEI
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PENICILLIN
RADIATION CHEMISTRY
RADIATION EFFECTS
RADIATIONS
RADICALS
RADIOISOTOPES
RADIOSENSITIVITY
RADIOSENSITIVITY EFFECTS
REACTION KINETICS
RESPONSE MODIFYING FACTORS
YEARS LIVING RADIOISOTOPES
560111* -- Radiation Effects on Biochemicals-- In Vitro-- (-1987)
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ALKALI METAL ISOTOPES
ANTIBIOTICS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
CESIUM 137
CESIUM ISOTOPES
CHALCOGENIDES
CHEMICAL RADIATION EFFECTS
CHEMISTRY
DATA
DOSE-RESPONSE RELATIONSHIPS
DRUGS
ELECTROMAGNETIC RADIATION
ELEMENTS
ENZYME INHIBITORS
EXPERIMENTAL DATA
GAMMA RADIATION
HYDROGEN
INACTIVATION
INFORMATION
IONIZING RADIATIONS
ISOTOPES
KINETICS
NITROGEN COMPOUNDS
NITROGEN OXIDES
NITROUS OXIDE
NONMETALS
NUCLEI
NUMERICAL DATA
ODD-EVEN NUCLEI
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PENICILLIN
RADIATION CHEMISTRY
RADIATION EFFECTS
RADIATIONS
RADICALS
RADIOISOTOPES
RADIOSENSITIVITY
RADIOSENSITIVITY EFFECTS
REACTION KINETICS
RESPONSE MODIFYING FACTORS
YEARS LIVING RADIOISOTOPES