title: Thermal stability of low molecular weight urokinase during heat treatment. II. Effect of polymeric additives.
abstract: Turbidimetric or light scattering assays can be used to determine the extent of aggregation in protein formulations. Using low molecular weight urokinase (LMW-UK) as a model protein, the effect of polymeric additives on heat-induced aggregation was evaluated. Previous work has shown that under 60 degrees C heat treatment, LMW-UK initially denatures and the unfolded protein associates to form soluble aggregates. Eventually, these aggregates associate to form a precipitate. The effects of polymers on the initial aggregation phase was examined. Hydroxyethyl (heta) starch, polyethylene glycol 4000, and gelatin were found to be effective, concentration-dependent inhibitors of aggregation, whereas polyvinylpyrrolidone (PVP) and polyethylene glycol 300 were ineffective. Overall, the effect of polymeric additives on the stability of thermally-stressed LMW-UK can be accounted for by preferential exclusion of the solute from the surface of the protein.
authors.affiliation: School of Pharmacy, University of Colorado Health Sciences Center, Denver 80262.
authors.forename: M
authors.initials: M
authors.lastname: Vrkljan
authors.forename: T M
authors.initials: TM
authors.lastname: Foster
authors.forename: M E
authors.initials: ME
authors.lastname: Powers
authors.forename: J
authors.initials: J
authors.lastname: Henkin
authors.forename: W R
authors.initials: WR
authors.lastname: Porter
authors.forename: H
authors.initials: H
authors.lastname: Staack
authors.forename: J F
authors.initials: JF
authors.lastname: Carpenter
authors.forename: M C
authors.initials: MC
authors.lastname: Manning
mesh_terms: D004795:Enzyme Stability; D005990:Glycerol / Q000494:pharmacology; D006358:Hot Temperature; D008027:Light; D008970:Molecular Weight; D009391:Nephelometry and Turbidimetry; D011092:Polyethylene Glycols; D011108:Polymers; D011205:Povidone; D011489:Protein Denaturation; D017510:Protein Folding; D012542:Scattering, Radiation; D013213:Starch / Q000494:pharmacology; D014568:Urokinase-Type Plasminogen Activator / Q000737:chemistry* / Q000187:drug effects
chemical_list: D011108:Polymers; D011092:Polyethylene Glycols; D013213:Starch; D014568:Urokinase-Type Plasminogen Activator; D011205:Povidone; D005990:Glycerol