AFFINITY PURIFICATION AND MICROCHARACTERIZATION OF RECOMBINANT DNA-DERIVED HUMAN GROWTH-HORMONE ISOLATED FROM AN IN-VIVO MODEL

A procedure has been developed for the isolation and purification of t race amounts of unlabeled proteins from biological solutions. Using a combination of affinity chromatography and reversed-phase HPLC, microg ram amounts of recombinant DNA-derived human growth hormone (rhGH) wer e purified from an in vivo rat model. Microcharacterization techniques were developed, and picomole amounts of the recovered protein were di gested with trypsin and characterized using capillary HPLC peptide map ping. The described procedures were used to study the chemical changes that occur in rhGH following intravenous administration. The study de monstrated that both deamidation and oxidation can occur in vivo, alth ough the former would occur to a significant extent only in proteins w ith an extended half-life.