Stabilization of proteins by guanidination.

摘要: Abstract Earlier studies have indicated the marked resistance of two pronase endopeptidases to denaturation in high concentrations urea or guanidine hydrochloride (Siegel, S., and Awad, W. M., Jr. (1973) J. Biol. Chem. 248, 3233--3240). One component has only a single residue lysine other none. The consideration arose that lysine-containing peptide segments may be less stable than those containing arginine because fluctuations side groups former residue. small epsilon amino not able sustain solvation hydrophobic arm an aqueous medium. Arginine residues shorter arms, larger hydrophilic groups, higher pKa values and, thus motile lysine. hypothesis was tested by guanidination seven globular proteins (bovine carbonic anhydrase, chymotrypsinogen, alpha-lactalbumin, serum albumin, ribonuclease, hen egg lysozyme, horse heart cytochrome c). Conversion homoarginine between 90 99%. Tritium-hydrogen isotope exchange revealed all except lysozyme demonstrated reduced out-exchange after guanidination. results with were unexpected since this protein ratio. These findings suggest ratios contribute stability.