Analysis of Methoxy-polyethylene Glycol-modified Human Serum Albumin

Modification of blood solutes with methoxy-polyethylene glycol (PEGylation) increases their size and half life in vivo. With three PEG reagents, we have created several species of PEGylated human serum albumins and examined their properties in vitro. Determination of size was undertaken with gel filtration, SDS-polyacrylamide gel electrophoresis, and surface enhanced laser desorption/ionization time of flight (SELDITOF)mass spectrometry. All demonstrated a significant increase in the size of the PEGylated albumin species, which was reflected in significant nonideal behavior during colloid osmotic pressure (COP) studies. Urea-induced protein unfolding experiments demonstrated that PEGylation does not significantly alter the stability of albumin’s fluorophore, tryptophanyl residue 214 (Trp 214). Solute-quenching studies of all but the most heavily modified albumin species monstrated no significant change in the fluorescent properties Trp 214. We believe PEGylated albumins have promise as resuscitative agents for hypoperfusion secondary to shock.