Patent ID: 8633157

Claim:
An erythropoietin peptide comprising a glycosyl linking group attached to an amino acid residue of said peptide, said glycosyl linking group comprising a modified sialyl residue having the formula: wherein R 2 is H, CH 2 OR 7 , COOR 7 , COO − , or OR 7 , wherein R 7 represents H, substituted or unsubstituted alkyl, or substituted or unsubstituted heteroalkyl; R 3 and R 4 are members independently selected from H, substituted or unsubstituted alkyl, OR 8 , and NHC(O)R 9 wherein R 8 and R 9 are independently selected from H, substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, and sialic acid; L a is a linker selected from C(O)NH and (CH 2 ) j C(O)NH(CH 2 ) h (CONH), wherein h and j are integers independently selected from 0 to 10; R 16 and R 17 are polymeric moieties independently selected from poly(amino) acids and PEG; X 2 and X 4 are linkage fragments independently selected from S, SC(O)NH, HNC(O)S, SC(O)O, O, NH, NHC(O), (O)CNH, NHC(O)O, OC(O)NH, CH 2 S, CH 2 O, CH 2 CH 2 O, and CH 2 CH 2 S; and X 5 is a member selected from H, unsubstituted alkyl, and unsubstituted heteroalkyl.