Diphtheria toxin fragments, conjugates and methods of use to inhibit tumors and leukemia

摘要

This invention relates to a modified diphtheria toxin (DT) and method of preparing the same in which two carboxy-terminal truncated forms of DT are prepared by specific chemical proteolysis generating two new proteins HA51DT and HA48DT which can be chemically linked to a cell specific binding moiety to produce potent cytotoxins. This invention further relates to carboxy terminal peptides formed in accordance with said proteolysis generating three peptides HA11DT, HA7DT and HA3DT.