Inactivation of the iron-containing superoxide dismutase of escherichia coli by hydrogen peroxide

Conference · Thu May 01 04:00:00 EDT 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:5217384

Beyer, Jr, W F; Fridovich, I

The iron-containing Fe(SOD) and the copper and zinc-containing (Cu,ZnSOD) superoxide dismutases (SOD) are inactivated by H/sub 2/O/sub 2/; whereas the corresponding manganese-containing enzyme (MnSOD) is resistant to H/sub 2/O/sub 2/. In the case of Cu, ZnSOD, studies of the effects of pH on inactivation demonstrated that HO/sub 2//sup -/ was the damaging species; while amino acid analysis showed that a loss of a single histidine per subunit correlated with loss of activity. The FeSOD from E. coli is inactivated to a limit of 90% by H/sub 2/O/sub 2/. The 10% residual H/sub 2/O/sub 2/-resistant activity differs form the activity of the native enzyme in being more sensitive to thermal inactivation and less sensitive towards inhibition by azide. Inactivation of FeSOD by H/sub 2/O/sub 2/ correlated with (1) loss of tryptophan and of iron, but not of histidine; (2) bleaching of absorption in the visible and alteration of the UV spectrum; and (3) increase in the intrinsic fluorescence due to tryptophan residues. Reversible removal of the iron demonstrated that the 10% H/sub 2/O/sub 2/-resistant activity of FeSOD was not due to some occupancy of the Fe site by manganese. Compounds such as histidine and urate, which protect Cu,ZnSOD against inactivation by H/sub 2/O/sub 2/, did not protect FeSOD.

• Research Organization: Duke Univ., Durham, NC
• OSTI ID: 5217384
• Report Number(s): CONF-8606151-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 45:6
• Country of Publication: United States
• Language: English

Related Subjects

550200 -- Biochemistry
560302* -- Chemicals Metabolism & Toxicology-- Microorganisms-- (-1987)
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AMINO ACIDS
AROMATICS
AZAARENES
AZOLES
BACTERIA
BIOLOGICAL EFFECTS
CARBOXYLIC ACIDS
COPPER
ELEMENTS
ENZYME ACTIVITY
ENZYMES
ESCHERICHIA COLI
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HISTIDINE
HYDROGEN COMPOUNDS
HYDROGEN PEROXIDE
IMIDAZOLES
INDOLES
IRON
MANGANESE
METALS
MICROORGANISMS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXIDOREDUCTASES
OXYGEN COMPOUNDS
PEROXIDES
PH VALUE
PYRROLES
SUPEROXIDE DISMUTASE
TRANSITION ELEMENTS
TRYPTOPHAN
ZINC