A PROCESS OF PREPARING A PROTEASE INHIBITOR

1,269,163. Preparation of protease inhibitor. SPOFA UNITED PHARMACEUTICAL WORKS. 19 May, 1970 [19 May, 1969], No. 24065/70. Heading A5B. Protease inhibitor is obtained from pancreas, e.g. of pigs or cattle, by first extracting the insulin by means of an acid aqueous ethanolic medium (70% ethanol), treating the residue with 60-70% aqueous ethanol at pH 10 to 13, removing the alcohol and precipitating lipoids by cooling, precipitating protein with ammonium or magnesium sulphate, preparing an aqueous suspension of the precipitate at 50 to 80‹C and with a pH of 5.5-7.5 by addition of trichloroacetic or sulphosalicylic acid, cooling, removing the precipitated ballast protein, adjusting the filtrate to pH 7.0 to 7.5, saturating it with NaCC and adding HCl to pH 1 to 3 to precipitate the inhibitor, which may be further purified by conventional procedures.