PREPARATION OF A RECOMBINANT SINGLE COPY POLYPEPTIDE OR PORTION THEREOF MODIFIED WITH A TERMINAL ALPHA AMINO CARBON REACTIVE GROUP AND REACTIVE SIDE CHAIN GROUPS INVOLVING BIOLOGICALLY ADDED PROTECTIVE GROUPS

摘要

The present invention provides for a method of preparing a modified recombinantly produced polypeptide including a reactive side chain group and a modified N-terminal alpha -amine group or C-terminal alpha -carboxyl group, the method comprising the steps of recombinantly forming a polypeptide having a biologically added protecting group on an N-terminal alpha -amine group or C-terminal alpha -carboxyl group, cleaving the biologically added protecting group with a cleavage reagent to form the unprotected terminal amino acid alpha -carbon reactive group and modifying the unprotected terminal amino acid alpha -carbon reactive group with a chemical modifying agent to form a terminally modified polypeptide. The invention further provides for a biologically added protecting group for a recombinantly produced polypeptide comprising a peptide or amino acid, said biologically protecting group being stable under conditions for chemical protecting reactions and including an enzymatic cleavage recognition site and a chemical cleavage recognition site, wherein the recognition sites are not present in the recombinantly produced polypeptide.