Binding and aggregation of human gamma-globulin by cis-diamminedichloroplatinum(II) through disulfide bond.
The incubation of gamma-globulin with cis-diamminedichloroplatinum (II) (cis-DDP) resulted in gradual formation of insoluble aggregates. Since the precipitates, composed of polymerized gamma-globulin and cis-DDP, were completely solubilized with urea, the reaction mixture containing precipitate was examined in terms of the binding of cis-DDP and the effect on disulfide (S-S) bonds in the gamma-globulin. When gamma-globulin was incubated with 30 molar excess cis-DDP at pH 7.4 and 37 degrees C, cis-DDP gradually bound to as much as 12 mol per mol of gamma-globulin in 14 d. Concurrently, about four disulfide bonds were cleaved without reaching a certain plateau. An sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of the aggregated gamma-globulin induced by cis-DDP was significantly different from that of the heat-denaturated aggregate form or the reduced form by sulfitolysis. The aquated complexes of cis-DDP also produced an insoluble precipitate and affected the S-S bond to a greater extent than the parent drug.
Chen
D
D
Faculty of Pharmaceutical Sciences, Nagoya City University, Japan.
Ohta
N
N
Ukai
M
M
Masuda
M
M
Yotsuyanagi
T
T
D002945:Cisplatin / Q000737:chemistry*; D004220:Disulfides / Q000737:chemistry*; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D009391:Nephelometry and Turbidimetry; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D011485:Protein Binding; D011489:Protein Denaturation; D005719:gamma-Globulins / Q000737:chemistry*
D004220:Disulfides; D005719:gamma-Globulins; D002945:Cisplatin; D010100:Oxygen