Vincristine-Induced Self-Association of Calf Brain Tubulin.

Prakash, V. and Timasheff, S. N. (1985) Vincristine-Induced Self-Association of Calf Brain Tubulin. Biochemistry, 24. pp. 5004-5010. ISSN 0006-2960

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Abstract

The vincristine-induced self-association of tubulin has been examined in a sedimentation velocity study as a function of free drug concentration in PG buffer (0.01 M Napi and lo4 M GTP, pH 7.0) at 20 OC. Analysis of the weight-average sedimentation coefficient (Sz0,+,,) as a function of protein concentration showed a good fit with the model of an indefinite, isodesmic self-association mechanism. Analysis of the apparent association constants in terms of the Wyman linkage relations showed a good fit to mediation of the self-association by the binding of one ligand molecule. The intrinsic association constant for dimerization of the vincristine-liganded tubulin was found to be 3.8 X IO5 M-’, and the intrinsic equilibrium constant for the binding of the self-association-linked vincristine molecule had a value of 3.5 X lo4 M-’, consistent with that measured by fluorescence in our laboratory [Prakash, V., & Timasheff, S. N. (1983) J. Biol. Chem. 258, 1689-16971, Both reactions are stronger in the presence of vincristine than of vinblastine, reflecting the oxidation of a -CH3 group to -CHO when going from the latter drug to the former one.

Item Type:	Article
Uncontrolled Keywords:	vincristine, vinca alkaloid, periwinkle plant, Tubulin, calf brains
Subjects:	500 Natural Sciences and Mathematics > 07 Life Sciences > 03 Biochemistry & Molecular Biology > 01 Alkaloid Biochemistry
Divisions:	Protein Chemistry and Technology
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	02 Jul 2018 06:02
Last Modified:	02 Jul 2018 06:02
URI:	http://ir.cftri.res.in/id/eprint/13546

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