Isolation, structural characterization, and antiviral activity of positional isomers of monopegylated interferon alpha-2a (PEGASYS).

Interferon alpha-2a plays an essential role in the treatment of chronic hepatitis C, but it is limited in its efficacy by the short in vivo half-life. To improve the half-life and efficacy, interferon alpha-2a is conjugated with a 40-kDa branched polyethylene glycol moiety (PEG-IFN, PEGASYS). From this preparation the positional PEG-IFN isomers were isolated and characterized by different analytical methods and antiviral assay.

New metal chelate adsorbent selective for proteins and peptides containing neighbouring histidine residues.

A novel nitrilotriacetic acid adsorbent has been prepared for metal chelate affinity chromatography. The new resin is a quadridentate chelate former and specially suitable for metal ions with coordination numbers of six, since two valencies remain for the reversible binding of biopolymers. It has been found to chelate Cu2+ and Ni2+ strongly and to be superior to the known iminodiacetic acid adsorbent.