Distinct and overlapping binding sites for IKP104 and vinblastine on tubulin

Asish Ray Chaudhuri, Isao Tomita, Fukutaro Mizuhashi, Kyoji Murata, Richard F. Ludueña

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


IKP104 is one of a group of tubulin-binding drugs whose interaction with tubulin suggests that it may bind to the protein at or close to the region where vinblastine binds. By itself IKP104 is a potent enhancer of tubulin decay as evidenced by the fact that it induces the exposure of the sulfhydryl groups and hydrophobic areas on tubulin. In this respect, IKP104 differs from vinblastine and other drugs such as phomopsin A, dolastatin 10, rhizoxin, and maytansine which are competitive or noncompetitive inhibitors of vinblastine binding. In contrast, however, in the presence of colchicine, IKP104 behaves differently and strongly stabilizes tubulin, to an extent much greater than dose colchicine alone. IKP104 appears to have two classes of binding site on tubulin, differing in affinity; the acceleration of decay appears to be mediated by the low-affinity site (Chaudhuri et al., 1998, J. Protein Chem., in press). We investigated the relationship of the binding of IKP104 and vinblastine. We found that the high-affinity site or sites of IKP104 overlap with or interact with the vinblastine-binding sites, but that the low- affinity site is distinctly different.

Original languageEnglish (US)
Pages (from-to)685-690
Number of pages6
JournalJournal of Protein Chemistry
Issue number7
StatePublished - Oct 1998
Externally publishedYes


  • Hydrophobic areas
  • IKP104
  • Sulfhydryl
  • Tubulin
  • Vinblastine

ASJC Scopus subject areas

  • Biochemistry


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