Methods for rational pegylation of proteins

A method of identifying at least one favorable attachment site for a polymeric moiety on a target protein comprising:

• a) inputting a set of coordinates into a computer for said target protein;
• b) inputting a set of coordinates for said polymeric moiety;
• c) selecting a criteria for said favorable attachment site based upon at least one desired characteristic,
• d) using a simulation module comprising the steps of:
• i) computationally attaching conformers of said polymeric moiety to a plurality of amino acids in said target protein;
• and
• ii) disallowing conformers at each of said amino acids on the basis of a distance cutoff;
• e) selecting based upon said criteria one of said amino acids for attachment of said polymeric moiety;
• and
• f) physically making and screening for said at least one desired characteristic at least one target protein with a polymeric moiety attached at said favorable attachment site amino acid position.