Thermal stability and enzymatic activity of RNase A in the presence of cationic gemini surfactants.
The thermal stability and enzymatic activity of bovine pancreatic ribonuclease A (RNase A) have been investigated in the presence of a homologous series of cationic gemini surfactants (alkanediyl-α,ω-bis(hydroxyethyl methyl hexadecyl ammonium bromide)). UV, circular dichorism and fluorescence spectroscopies have been used for this study. The denaturation curves at various surfactant concentrations were analyzed on basis of a two-transition model to obtain values of T(m) (temperature at the midpoint of denaturation) and ΔH(m) (enthalpy change at T(m)) of each transition. The main conclusion of this study is that these cationic gemini surfactants slightly activate and stabilize RNase A below their critical micelle concentrations at pH 5.0. The cationic gemini surfactant with the shorter spacer interacts more efficiently with RNase A than those with longer spacers.
Department of Chemistry, University of Isfahan, Isfahan, Iran.
Razieh
R
Amiri
Abdol-Khalegh
AK
Bordbar
Douglas V
DV
Laurents
Ahmad Reza
AR
Khosropour
Iraj
I
Mohammadpoor-Baltork
D004795:Enzyme Stability / Q000187:drug effects; D004983:Ethanolamines / Q000737:chemistry* / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D011487:Protein Conformation; D011489:Protein Denaturation / Q000187:drug effects; D000644:Quaternary Ammonium Compounds / Q000737:chemistry* / Q000494:pharmacology*; D012259:Ribonuclease, Pancreatic / Q000737:chemistry* / Q000378:metabolism*; D013057:Spectrum Analysis; D013501:Surface-Active Agents / Q000737:chemistry* / Q000494:pharmacology*; D013696:Temperature
D004983:Ethanolamines; C400066:N,N-di-n-hexadecyl-N,N-dihydroxyethylammonium; D000644:Quaternary Ammonium Compounds; D013501:Surface-Active Agents; D012259:Ribonuclease, Pancreatic