Effects of Ce3+ on conformation and activity of superoxide dismutase.
Ce3+ in various concentrations was added to superoxide dismutase (SOD) from rat eryhrocyte in vitro to gain insight into the mechanism of molecular interactions between Ce3+ and SOD. The results showed that the reaction between SOD and Ce3 was two order, which meant that the SOD activity was markedly accelerated by a low concentration of Ce3+ and inhibited by a high concentration of Ce3+. The spectroscopic assays suggested that the Ce3+ was determined to directly bind to SOD; the binding site of Ce3+ to SOD was 0.96, and the binding constants (K(A)) were 6.78 x 10(5) and 1.68 x 10(5)L.mol(-1); the binding Ce3+ entirely altered the secondary structure of SOD. It implied that the Ce(3+) coordination created a new metal ion-active site form in SOD, thus leading to an enhancement in SOD activity.
Liu
Jie
J
Medical College of Soochow University, Suzhou, 215123, People's Republic of China.
Ma
Linglan
L
Yin
Sitao
S
Hong
Fashui
F
D000818:Animals; D002412:Cations / Q000737:chemistry / Q000494:pharmacology; D002417:Cattle; D002586:Cesium / Q000737:chemistry / Q000494:pharmacology*; D002942:Circular Dichroism; D004789:Enzyme Activation / Q000187:drug effects; D011487:Protein Conformation / Q000187:drug effects; D051381:Rats; D013053:Spectrophotometry; D013482:Superoxide Dismutase / Q000737:chemistry* / Q000378:metabolism*
D002412:Cations; D002586:Cesium; D013482:Superoxide Dismutase