Cancer letters
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Cryptophycin 1 is a new cytotoxic antimicrotubule agent with excellent antitumor activity. The methods of Sackett (Biochemistry, 34, 7010-7019, 1995), utilizing the selective and specific proteolysis of alpha- and beta-tubulin by trypsin and chymotrypsin, was used to identify the cryptophycin 1 binding site on tubulin. ⋯ The effects of cryptophycin 1 on the tryptic digests are identical to the effects seen with vinblastine and differ saliently from the effects of maytansine and rhizoxin, other agents known to bind to the vinca site. The data suggest that the binding site of cryptophycin 1 may overlap the vinca binding site on tubulin.