Enzymatic cleavage of peptide-linked radiolabels from immunoconjugates.
We have incorporated peptides selected by combinatorial library [Peterson, J. J., and Meares, C. F. (1998) Bioconjugate Chem. 9, 618-626) into peptide-linked radiolabeled immunoconjugates of the form DOTA-peptide-antibody. Decapeptide linkers -GFQGVQFAGF- and -GFGSVQFAGF-, selected for cleavage by human liver cathepsin B, were rapidly digested in vitro when compared to the simple model tetrapeptide motif of the prototype -GGGF- [Li, M., and Meares, C. F. (1993) Bioconjugate Chem. 4, 275-283]. Cleavage properties of these library-selected substrates for cathepsin B compared favorably with decapeptide linkers -GLVGGAGAGF- and -GGFLGLGAGF-, which incorporate two of the most labile extended cathepsin B substrates from the literature. The decapeptide linker -GFGSTFFAGF-, selected from the library for cleavage by human liver cathepsin D, was rapidly digested by cathepsin D while the others were not.
Department of Chemistry, University of California, One Shields Avenue, Davis, California 95616-5295, USA.
J J
JJ
Peterson
C F
CF
Meares
D002401:Cathepsin B / Q000737:chemistry; D002402:Cathepsin D; D002403:Cathepsins / Q000737:chemistry*; D002855:Chromatography, Thin Layer; D018796:Immunoconjugates / Q000737:chemistry*; D008099:Liver / Q000201:enzymology; D009842:Oligopeptides / Q000737:chemistry*; D019275:Radiopharmaceuticals / Q000737:chemistry*; D015021:Yttrium Radioisotopes
D018796:Immunoconjugates; D009842:Oligopeptides; D019275:Radiopharmaceuticals; D015021:Yttrium Radioisotopes; D002403:Cathepsins; D002401:Cathepsin B; D002402:Cathepsin D