Yasuhiko Nozaki

The solubilities of amino acids, diglycine, and triglycine have been measured in water and aqueous ethanol as well as dioxane solutions. Free energies of transfer of amino acid side chains and backbone peptide units from water to ethanol and dioxane solutions have been calculated from these data. The results show the similarity between the effects of ethanol and dioxane on the stability of those side chains and peptide units. In particular, the free energies of transfer of hydrophobic side chains to 100% ethanol and dioxane are essentially identical, and have been used to establish a hydrophobicity scale for hydrophobic side chains.

Removal of detergent from mixed micelles of egg yolk phosphatidylcholine and octyl glucoside leads to formation of unilamellar phospholipid vesicles with a diameter of about 230 nm. The same procedure applied to mixed micelles containing the transmembrane protein glycophorin A, in addition to lipid and detergent, produces vesicles of the same size with glycophorin incorporated into the bilayer. The pure lipid vesicles are highly impermeable to both anions and cations, and incorporation of up to 220 molecules of glycophorin per vesicle has little effect on permeability.

Abstract The solubilities of amino acids, diglycine, and triglycine have been measured in water and 1 m to 6 m guanidine hydrochloride solutions. Free energies of transfer of amino acid side chains and backbone peptide units from water to guanidine hydrochloride solutions have been calculated from these data. The results show similarity between the patterns of solubilizing effects of guanidine hydrochloride and urea, although guanidine hydrochloride is 2 to 3 times more effective than urea at the same concentrations.