Abstract: The invention provides bioconjugates of the formula: in which A is an active agent comprising an active hydroxy or amino functionality and B is a biopolymer comprising an active hydroxy or amino functionality, and X1 and X2 are independently N or O, and R is substituted alkyl or unsubstituted alkyl or unsubstituted or substituted heteroalkyl from 1 to about 30 atoms in length. The biopolymer may for instance be a transport protein or an antibody directed to a transport protein (e.g., a p97 protein or antibody thereto). The active agent may be a therapeutic agent such as a chemotherapeutic agent or an antineoplastic agent or an enzyme. The bioconjugates find therapeutic usages according to the therapeutic indications of the active agent. Methods of making the bioconjugates and bifunctional isocyanate cross linking reagents of use in making such bioconjugates are provided.

Abstract: The invention provides bioconjugates of the formula: 1