J. Chim. Phys.
Volume 61, 1964
|Page(s)||105 - 111|
|Published online||28 May 2017|
Hydrophobic bond. Activity and conformation of trypsin in dimethylsulfoxide-water systems
Chemistry Department, Adelphi College, Garden City, N.Y., U.S.A..
The behavior of trypsin was studied in dimethylsulfoxide-water binary systems of varying concentrations. Proteolytic activity was demonstrated over the whole range of solvents with casein and over a limited range with Thiogel. Minimal enzyme activity was found at 1 : 2 dimethylsulfoxide : water molar ratio. A compound formation in the solvent at this concentration was demonstrated by heat of mixing, viscosity and dielectric constant measurements. Solubility and light scattering measurements indicate a conformational change in the trypsin molecule with a maximum unfolding at the 1 : 2 molar ratio. The more active, folded state is partly due to hydrophobic bonds existing between non-polar side chains. Spectroscopic investigation as well as thermodynamic data from amino acid solubilities indicate that the aromatic side chains such as tyrosyl, tryptophanyl and phenylalanyl residues play the most important part in hydrophobic bonding.
© Paris : Société de Chimie Physique, 1964