[Modification of basic pancreatic trypsin inhibitor by fatty acid derivatives]

A procedure was developed for the modification of basic pancreatic trypsin inhibitor (BPTI) by N-hydroxysuccinimide esters of oleic and stearic acids in a DMSO-DMF-dioxane-pyridine mixture with a temporary citraconyl protection of the amino group belonging to its active site. The BPTI derivatives containing from one to three acylated amino groups were obtained. It was shown that the hydrophobized BPTI with one amino group modified retained practically the full activity of the native inhibitor. An increase up to three acylated groups resulted in a decrease in the specific activity of the inhibitor to 28% of the initial activity. An increase in hydrophobicity of the modified inhibitors was demonstrated by the spectral method and by the distribution in a water-triton X-114 system.