Preservation of the proteolytic activity of a bovine spleen lysosomal-enriched extract using various freezing conditions

• Published in: Enzyme and microbial technology Vol. 28; no. 4; pp. 453 - 459
• Main Authors: Melendo, Jesús A., Beltrán, José Antonio, Roncalés, Pedro
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 08.03.2001; Elsevier Science
• Subjects: Biological and medical sciences; Biotechnology; Cathepsins; Cryoprotectants; Enzyme engineering; Freezing; Fundamental and applied biological sciences. Psychology; Methods. Procedures. Technologies; Miscellaneous; Myofibrillar proteins; Proteases; Spleen; Spleen; Cathepsins; Proteases; Myofibrillar proteins; Freezing; Cryoprotectants; Freeze drying; Bovine; Enzyme; Conservation; Peptidases; Vertebrata; Cathepsin; Mammalia; Enzymatic activity; Hydrolases; Artiodactyla; Cryoprotective agent; Refrigeration; Ungulata
• ISSN: 0141-0229; 1879-0909
• DOI: 10.1016/S0141-0229(00)00354-9

The preservation of the proteolytic activity of a bovine spleen lysosomal-enriched (BSLE) extract was investigated. The BSLE extract (pH = 5.8), was subjected to storage under different conditions: refrigeration at 0°C for 60 days; freezing at −20°C —either directly or previously frozen in liquid nitrogen—, −80°C and in liquid nitrogen; freeze-drying and stored at 0°C; and freezing at −20°C or in liquid nitrogen in the presence of glycerol and sorbitol as cryoprotectants. Freezing at low temperatures (-80°C and in liquid nitrogen) was most effective for preserving about 100% of the initial activity of all cathepsins (B, B+L and D), as well as the activity of the extract on myofibrils, for two years. Freezing at −20°C, on the contrary, led to significant ( P < 0.01) losses of activity. Freeze-drying was able to preserve cathepsin activity, while it failed to maintain activity on myofibrils. Both cryoprotectants sorbitol and glycerol significantly ( P < 0.01) enhanced enzyme preservation, particularly cathepsin D and the activity on myofibrils, even at a freezing temperature of −20°C.