Re-formation of disulphide bonds in reduced antithrombin III.
Human antithrombin III (AT-III) contains three disulphide linkages (Cys-8-Cys-128, Cys-21-Cys-95 and Cys-247-Cys-430), and two of them (Cys-8-Cys-128 and Cys-21-Cys-95) are situated near the heparin-binding domain of the inhibitor. We demonstrate in this paper that: (i) partially reduced AT-III (with Cys-8-Cys-128 and Cys-21-Cys-95 quantitatively reduced) could be re-oxidized in air to regain 70-80% of its heparin cofactor activity and thrombin-inhibitory activity; (ii) completely reduced AT-III was re-oxidized under similar conditions and recovered 30-35% of it biological activities. Structural analysis of refolded AT-IIIs indicates that restorations of their disulphide contents and conformations (evaluated by chemical modification) are congruent with recoveries of their biological activities.
Sun
X J
XJ
Pharmaceuticals Research Laboratories, CIBA-GEIGY Ltd., Basel, Switzerland.
Chang
J Y
JY
D000990:Antithrombin III / Q000378:metabolism* / Q000502:physiology; D003488:Cyanogen Bromide / Q000378:metabolism; D004220:Disulfides / Q000378:metabolism*; D006801:Humans; D010084:Oxidation-Reduction; D010446:Peptide Fragments / Q000378:metabolism; D011487:Protein Conformation; D013329:Structure-Activity Relationship; D013917:Thrombin / Q000037:antagonists & inhibitors
D004220:Disulfides; D010446:Peptide Fragments; D000990:Antithrombin III; D013917:Thrombin; D003488:Cyanogen Bromide