title: PEGylation prevents the N-terminal degradation of megakaryocyte growth and development factor.
abstract: OBJECTIVE
  Determine the effect of PEGylation on in-vitro degradation for recombinant human Megakaryocyte Growth and Development Factor (rHuMGDF) in the neutral pH range.
  
  
  METHODS
  Degradation products were characterized by cation-exchange HPLC, N-terminal sequencing and mass spectrometry.
  
  
  RESULTS
  The main route of degradation was through non-enzymatic cyclization of the first two amino acids and subsequent cleavage to form a diketopiperazine and des(Ser, Pro)rHuMGDE This reaction was prevented by alkylation of the N-terminus by polyethylene glycol (PEG).
  
  
  CONCLUSIONS
  PEGylation of proteins is commonly performed to achieve increased in-vivo circulation half-lives. For rHuMGDF, an additional advantage of PEGylation was enhanced in-vitro shelf-life stability.
authors.affiliation: Department of Pharmaceutics, Amgen Inc., Thousand Oaks, California 91320, USA.
authors.forename: P I
authors.initials: PI
authors.lastname: Guerra
authors.forename: C
authors.initials: C
authors.lastname: Acklin
authors.forename: A A
authors.initials: AA
authors.lastname: Kosky
authors.forename: J M
authors.initials: JM
authors.lastname: Davis
authors.forename: M J
authors.initials: MJ
authors.lastname: Treuheit
authors.forename: D N
authors.initials: DN
authors.lastname: Brems
mesh_terms: D000478:Alkylation; D000900:Anti-Bacterial Agents; D002851:Chromatography, High Pressure Liquid; D054659:Diketopiperazines; D004356:Drug Storage; D006801:Humans; D006863:Hydrogen-Ion Concentration; D013058:Mass Spectrometry; D010446:Peptide Fragments / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D010449:Peptide Mapping; D010879:Piperazines; D011092:Polyethylene Glycols / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D013696:Temperature; D013926:Thrombopoietin / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D054659:Diketopiperazines; D010446:Peptide Fragments; D010879:Piperazines; D011994:Recombinant Proteins; C103117:polyethylene glycol-recombinant human megakaryocyte growth and development factor; D011092:Polyethylene Glycols; D013926:Thrombopoietin