Cryoprotective ability of betaine-type metabolite analogs during freezing denaturation of enzymes.

Nakagawa, Yuichi; Sota, Masahiro; Koumoto, Kazuya

Objective: To evaluate an analog library of betaine-type cellular metabolites, which are naturally found in polar fish for survival in subzero temperatures, for preventing denaturation of enzymes during freezing. Results: Comparison of the cryoprotective ability of reported cryoprotectants, such as dimethylsulfoxide, glycerol, ectoine, hydroxyectoine, and trehalose, with betaine-type analogs using α-glucosidase revealed that analogs introducing C-C alkyl chains into an ammonium cation retained 20 % higher activity than the control cryoprotectants at the same concentration. In particular, the analog possessing triplicate n-butyl chains showed a profound effect. It allowed retention of enzyme activity to 95 % even after 100 freeze-thaw cycles, while addition of the control cryoprotectants decreased the activity to 10-20 %. The cryoprotective ability of betaine-type analogs can be applied not only to α-glucosidase but also other enzymes such as β-glucosidase, alkaline phosphatase, lactose dehydrogenase, sulfatase, and horseradish peroxidase. Conclusion: Synthetic betaine-type metabolite analogs possess practicable cryoprotective ability for various enzymes, and are considerably superior to previously reported cryoprotectants.

CRYOPROTECTIVE agents; BETAINE; METABOLITES; ENZYMES; FREEZING; FISH research

Biotechnology Letters, 2015, Vol 37, Issue 8, p1607

0141-5492

Academic Journal

10.1007/s10529-015-1841-1