The role of metal ions in the radiosensitivity of metalloproteins. Model experiments with bovine carbonic anhydrase.
The radiation-induced inactivation of dilute solutions of three forms of bovine carbonic anhydrase (metal-free apo-BCA, Zn2+-BCA and Co2+-BCA) has been studied. The presence of the metal ions did not alter the sensitivity of the enzyme to inactivation by oxidizing radicals; however, they exerted a protective effect against inactivation by reducing radicals. Data obtained using the amino-acid-specific inorganic radical anions (CNS)2-and Br2-allowed the identification of histidine, tyrosine and tryptophan as residues essential to the activity of bovine carbonic anhydrase when assayed by p-nitro-phenylacetate.
D002256:Carbonic Anhydrases / Q000528:radiation effects*; D003300:Copper; D004583:Electrons; D005609:Free Radicals; D011830:Radiation Effects; D015032:Zinc
D005609:Free Radicals; D003300:Copper; D002256:Carbonic Anhydrases; D015032:Zinc