| abstract |
PEG linker compounds and biologically active conjugates thereof having mixed functional group linkages attached to at least one PEG moeity, and a coupling group for attaching a biologically active molecule. The PEG mixed linkages can be the combinations of stable, or labile, or releasable, or stable and labile, or stable and releasable, or releasable and labile covalent linkages. The mixed functional linkages of the PEG linker compounds consist of different organic functional groups, which have non-equivalent half-life in plasma and, hence, they have different release rates in blood. The present invention also provides for attachment of novel PEG linker compounds with mixed functional linkages for Pegylation of biologically active molecules to produce Probiomolecule-PEG constructs. The Probiomolecule-PEG construct is the prodrug of biomolecule-PEG conjugate or biomolecule. The Probiomolecule-PEG conjugate will gradually lose portions (or all) of its PEG polymers in vivo to convert into smaller size biomolecule-PEG conjugate (or biologically active molecule), thereby increasing their biological activity in vivo. |