Improved process for the preparation of enzyme extracts from liver and extracts so produced

摘要

Enzyme extracts (particularly catalase, cathepsin and arginase) are obtained from enzymebearing mammalian liver tissue by treating them with water to obtain an aqueous enzyme extract and bringing the pH of the latter to 5.0-5.6 to precipitate impurities. The tissues may be extracted at pH 6.0-7.0 and the extract then acidified, or both steps may be carried out at 5.0-5.6. Preferred conditions are pH 6.3-6.7 for the extraction and 5.2-5.4 for the precipitation. The liver material may, before extraction, be washed at below 0 DEG C. with an aqueous organic solvent (lower primary alcohol or acetone) at a concentration of 30-70 per cent. Preferably 40-50 per cent ethanol is used at - 3 DEG to - 15 DEG C. The purified enzyme extract after treatment at pH 5.0-5.6 is fractionally precipitated (below 0 DEG C.) with 15-60 per cent ethanol or methanol at pH 4.2-7.4, the ionic strength being below 0.2. Preferred conditions for this step are pH 5.4-6.2, ionic strength below 0.1, temperature - 3 DEG to - 15 DEG C. and alcohol concentration 20-50 per cent. The amorphous precipitate so obtained (containing catalase and cathepsin) is dissolved in water at pH above 5.8 (preferably buffered) and the pH then reduced to 5.1-6.3 to crystallize the catalase. Cathepsin can be obtained from the supernatant liquor. Examples are given of the production of catalase and cathepsin from comminuted beef and hog liver tissues.