Accessibility and structural function of particular amino acid residues of soy bean trypsin inhibition

摘要: Abstract About 10 of the 11 lysine groups soy bean trypsin inhibitor (STI) are accessible to reaction with methyl isourea. The guanidinated product has same trypsin-inhibiting capacity as original, although some activity is lost by a urea denaturation-renaturation cycle. From perturbation spectra tryptophan STI behave formally if 67% exposed solvent at pH 7. Only one group oxidized N-bromosuccinimide in water 4–6, minor loss activity. Most residual survives Three tryptophans for denatured m urea, nearly complete Two H2O2 8.6 inactivation. tyrosine iodinated at, 8–9, only remains after Iodination results all four tyrosines, total Both histidine react diazonium-1-H-tetrazole. This, together kinetics imidazole-catalyzed hydrolysis p-nitrophenol acetate, suggests that both histidines solvent.