PURPOSE: To investigate the factors that contribute to the exceptionally high affinity binding of UCN-01 to human alpha1-acid glycoprotein (hAGP). METHODS: Interactions between UCN-01, UCN-02, and staurosporine with native and chemically modified hAGPs were examined using ultracentrifugation and spectroscopic analysis. RESULTS: The binding affinity of staurosporine, as well as UCN-02, to hAGP was lower than that of UCN-01 by 20- and 100-fold respectively. The percentage of UCN-01 that binds to hAGP was low at acidic pH but increased with increasing pH, reaching a maximum at pH 7.4. The binding of UCN-01 to desialylated hAGP was comparable to that of hAGP. No significant difference was found for the binding of UCN-01 to F1*S and A variants of hAGP. Chemical modification of the His, Lys, Trp, and Tyr residues caused a decrease in percentage of bound UCN-01. Trp-modified hAGP showed the largest decrease in binding. Tryptophanyl fluorescence quenching results indicate that Trp residues play a prominent role in the binding of UCN-01 to hAGP. CONCLUSIONS: A substituent at position C-7 of UCN-01 appeared to influence the binding specificity of the drug, and Trp residues in hAGP play a prominent role in the high affinity binding of UCN-01 to hAGP.
PURPOSE: To investigate the factors that contribute to the exceptionally high affinity binding of UCN-01 to human alpha1-acid glycoprotein (hAGP). METHODS: Interactions between UCN-01, UCN-02, and staurosporine with native and chemically modified hAGPs were examined using ultracentrifugation and spectroscopic analysis. RESULTS: The binding affinity of staurosporine, as well as UCN-02, to hAGP was lower than that of UCN-01 by 20- and 100-fold respectively. The percentage of UCN-01 that binds to hAGP was low at acidic pH but increased with increasing pH, reaching a maximum at pH 7.4. The binding of UCN-01 to desialylated hAGP was comparable to that of hAGP. No significant difference was found for the binding of UCN-01 to F1*S and A variants of hAGP. Chemical modification of the His, Lys, Trp, and Tyr residues caused a decrease in percentage of bound UCN-01. Trp-modified hAGP showed the largest decrease in binding. Tryptophanyl fluorescence quenching results indicate that Trp residues play a prominent role in the binding of UCN-01 to hAGP. CONCLUSIONS: A substituent at position C-7 of UCN-01 appeared to influence the binding specificity of the drug, and Trp residues in hAGP play a prominent role in the high affinity binding of UCN-01 to hAGP.
Authors: E A Sausville; S G Arbuck; R Messmann; D Headlee; K S Bauer; R M Lush; A Murgo; W D Figg; T Lahusen; S Jaken; X Jing ; M Roberge; E Fuse; T Kuwabara; A M Senderowicz Journal: J Clin Oncol Date: 2001-04-15 Impact factor: 44.544
Authors: David Komander; Gursant S Kular; Jennifer Bain; Matthew Elliott; Dario R Alessi; Daan M F Van Aalten Journal: Biochem J Date: 2003-10-15 Impact factor: 3.857
Authors: E Fuse; H Tanii; N Kurata; H Kobayashi; Y Shimada; T Tamura; Y Sasaki; Y Tanigawara; R D Lush; D Headlee; W D Figg; S G Arbuck; A M Senderowicz; E A Sausville; S Akinaga; T Kuwabara; S Kobayashi Journal: Cancer Res Date: 1998-08-01 Impact factor: 12.701
Authors: F Hervé; G Caron; J C Duché; P Gaillard; N Abd Rahman; A Tsantili-Kakoulidou; P A Carrupt; P d'Athis; J P Tillement; B Testa Journal: Mol Pharmacol Date: 1998-07 Impact factor: 4.436