title: [Stabilization of diluted aqueous solutions of horseradish peroxidase].
abstract: Effects of pH, enzyme concentration, and various supplements on the catalytic activity, temperature stability, and secondary structure of horseradish peroxidase (HRP) were studied in diluted aqueous solutions. In 5.0 mM citrate-phosphate buffer (pH 4.2) at 55 degrees C and infinite dilution, HRP was inactivated with a rate constant of 2.86 x 10(-3) s-1. CaCl2, BSA, and glycerol caused protective effects, whereas KCl, LiCl, maltose, PEG-6000 (at a concentration above 3%), Triton X-100, ethanol, and Kathon CG had an opposite effect and altered the secondary structure of HRP. Two HRP-stabilizing media: the "glycerol-based" one containing 10% ethanol and 20% glycerol, or the "protein-based" one containing 0.1% Kathon CG and 0.2 g/l of BSA in 50.0 mM Tris-HCl buffer (pH 7.2) supplemented with 50 mM CaCl2 were developed, and the stability of HRP (0.36 nM) and its immunoglobulin, cortisol, and progesterone conjugates were compared in these two media. The protein-based medium displayed a greater stabilizing effect particularly on HRP-steroid conjugates.
authors.affiliation: Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus, Minsk, Belarus 220141.
authors.forename: A N
authors.initials: AN
authors.lastname: Eremin
authors.forename: L P
authors.initials: LP
authors.lastname: Budnikova
authors.forename: O V
authors.initials: OV
authors.lastname: Sviridov
authors.forename: D I
authors.initials: DI
authors.lastname: Metelitsa
mesh_terms: D002021:Buffers; D002122:Calcium Chloride / Q000494:pharmacology; D002384:Catalysis; D004795:Enzyme Stability / Q000187:drug effects; D000431:Ethanol / Q000494:pharmacology; D005990:Glycerol / Q000494:pharmacology; D006735:Horseradish Peroxidase / Q000737:chemistry*; D017433:Protein Structure, Secondary; D012710:Serum Albumin, Bovine / Q000494:pharmacology; D013696:Temperature
chemical_list: D002021:Buffers; D012710:Serum Albumin, Bovine; D000431:Ethanol; D006735:Horseradish Peroxidase; D002122:Calcium Chloride; D005990:Glycerol