ABSTRACT
This study was aimed at the comparative evaluation of stabilizing additives used for the protection of the antiviral activity of interferon-alpha2b against thermal inactivation, at 60 degrees C. The comparative effects of amino acids, polyhydric alcohols, saccharides and nonionic surfactants were studied. All were effective. Representing the thermal inactivation process with first order kinetics, a maximal prolongation of antiviral activity half-life of 39-fold was achieved with the most effective procedure. Inactivation rate constants varied from (53.3+/-4.6)x10(-3) to (2.5+/-0.3)x10(-3) min(-1). Human serum albumin, nonionic surfactants and monosaccharides increased half-life values by 5-39-, 5-23-, 4-20-fold, respectively. Amino acids, polyhydric alcohols and disaccharides increased t(1/2) values by 4-11-, 2-8- and 3-8-fold, respectively. These data provide useful information for the selection of stabilizing additives for IFN-alpha2b formulations.
Subject(s)
Antiviral Agents/pharmacology , Interferon-alpha/pharmacology , Protective Agents/pharmacology , Alcohols/pharmacology , Amino Acids/pharmacology , Antiviral Agents/therapeutic use , Cell Line, Transformed , Disaccharides/pharmacology , Drug Interactions , Drug Stability , Half-Life , Humans , Hydrogen-Ion Concentration , Interferon alpha-2 , Maus Elberfeld virus/drug effects , Microbial Sensitivity Tests , Monosaccharides/pharmacology , Recombinant Proteins , Serum Albumin/pharmacology , Surface-Active Agents/pharmacologyABSTRACT
Zn(2+) and Co(2+) ions are known to promote human growth hormone reversible dimerization. In these studies, dimerization was also shown to be initiated by nine other metal ions: Cd(2+), Hg(2+), Cu(2+), Ag+, Au(3+), Au+, Pd(2+), Ni(2+), and Pt(4+). In some cases (Hg(2+), Ag(+), Au(3+), and Ni(2+)) formation of higher oligomers also took place. In addition further detailed investigation of dimerization in the presence of Zn(2+) ions was carried out.
Subject(s)
Human Growth Hormone/chemistry , Metals, Heavy/pharmacology , Amino Acid Sequence , Cations , Cross-Linking Reagents , Dimerization , Human Growth Hormone/drug effects , Humans , Molecular Sequence Data , Peptide Fragments/chemistry , Triazines/pharmacology , TrypsinABSTRACT
Six difunctional and trifunctional derivatives of acrylamide were synthesized and investigated as potential protein lysine residue cross-linking agents. 1,3,5-Triacryloyl-hexahydro-s-triazine (TAT) was considered the best. The rate constants for the reactions of TAT with model nucleophiles in water solution at 25 degreesC were with the glycine anion amino group, 7.69 x 10(-3) M-1 s-1; with the anionic form of the N-acetyl-L-cysteine thiol group, 5.54 M-1 s-1; and with the Nalpha-acetyl-L-histidine imidazole ring, 1.19 x 10(-5) M-1 s-1 (at pH 9.0). The kinetics of modification of amino groups by TAT were studied for several proteins: alpha1-casein, bovine serum albumin, recombinant human growth hormone, recombinant human interferons-alpha2b, and -gamma. The results indicate that if proteins are associated into oligomeric structures in water, their subunits are effectively cross-linked by TAT.
