AN X-RAY-ABSORPTION STUDY OF THE RECONSTITUTION PROCESS OF BOVINE CU,ZN SUPEROXIDE-DISMUTASE BY CU(I)-GLUTATHIONE COMPLEX

The Cu(I)GSH complex has recently been shown to be a good candidate fo r delivering copper to the active site of Cu-free Cu,Zn superoxide dis mutase both in vivo and in vitro. In this work X-ray absorption spectr oscopy has been used to characterize the Cu(I)GSH complex and to follo w in vitro the reconstitution of Cu,Zn superoxide dismutase from the c opper-free protein and this complex. The results obtained indicate tha t the copper is directly transferred as Cu(I) from the GSH complex int o the empty copper binding site. No evidence has been obtained for a t ernary complex in which the metal is bound to both GSH and the protein .