Determination of binding constants and stoichiometries for platinum anticancer drugs and serum transport proteins by capillary electrophoresis using the Hummel-Dreyer method.
A CE method has been developed to evidence and quantitatively characterize the interaction between platinum-based antitumor drugs and human serum proteins. This method is a variant of affinity CE modified regarding both experimental setup and data treatment so as to measure the peaks (or vacancies) that correspond to the bound drug when it slowly binds to the protein. Using the formalism of the Hummel-Dreyer method and cisplatin and oxaliplatin as test compounds, a protocol for determining albumin and transferrin binding constants and stoichiometries, including (and distinguished by) 48 hours of incubation of the reaction mixture, was elaborated. Relative affinities of drugs toward different proteins in aqueous solution at physiological pH, chloride concentration, and temperature were compared in terms of overall binding constants and numbers of drug molecules attached to the protein. The results indicate that both platinum drugs bind to albumin more strongly than to transferrin, supporting the concept that the albumin fraction is a major drug supply route for chemotherapeutical needs. From a comparison with the binding parameters measured previously for cisplatin by other methods, conclusions were drawn about the validity of CE as a simple and convenient method for assaying protein-drug reactions with slow kinetics.
Rudnev
Alexander V
AV
Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, 117975 Moscow, Russia.
Aleksenko
Svetlana S
SS
Semenova
Olga
O
Hartinger
Christian G
CG
Timerbaev
Andrei R
AR
Keppler
Bernhard K
BK
D000418:Albumins / Q000737:chemistry; D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology*; D001692:Biological Transport; D001798:Blood Proteins / Q000737:chemistry; D002138:Calibration; D002352:Carrier Proteins / Q000737:chemistry; D002712:Chlorides / Q000737:chemistry; D002945:Cisplatin / Q000737:chemistry / Q000494:pharmacology; D004573:Electrolytes / Q000737:chemistry; D019075:Electrophoresis, Capillary / Q000379:methods*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D015233:Models, Statistical; D009944:Organoplatinum Compounds / Q000737:chemistry / Q000494:pharmacology; D000077150:Oxaliplatin; D004364:Pharmaceutical Preparations / Q000737:chemistry; D010984:Platinum / Q000737:chemistry; D011485:Protein Binding; D013696:Temperature; D013997:Time Factors; D014168:Transferrin / Q000737:chemistry
D000418:Albumins; D000970:Antineoplastic Agents; D001798:Blood Proteins; D002352:Carrier Proteins; D002712:Chlorides; D004573:Electrolytes; D009944:Organoplatinum Compounds; D004364:Pharmaceutical Preparations; D014168:Transferrin; D000077150:Oxaliplatin; D010984:Platinum; D002945:Cisplatin