Patent ID: 8404804

Claim:
A method for forming an amide bond between a first molecule having a thioester moiety and a second molecule having an N—(C 1 -C 5 )-cysteine (SEQ ID NO:1) residue having an unoxidized sulfhydryl moiety, comprising the steps of: (a) reacting said thioester moiety of the first molecule with said unoxidized sulfhydryl moiety of the N—(C 1 -C 5 )-cysteine (SEQ ID NO:1) residue of the second molecule to generate an intermediate connecting the first and second molecules with a β-(C 1 -C 5 amino)-thioester linkage; and (b) allowing the β-(C 1 -C 5 amino)-thioester linkage of the intermediate to rearrange intramolecularly to from an amide bond connecting said first and second molecules.