Cryoprotectants, which are essential for minimizing cryoinjury during freezing, can be toxic to biological systems. Monohydric alcohols, dimethyl sulfoxide (Me<sup>2</sup>SO), and ethylene glycol (EG), are known to denature enzymes at room temperature. In this study, rosy barb (Puntius conchonius) and zebra fish (Brachydanio rerio) embryos at cleavage, epiboly, and closure of blastopore stages were exposed to Me<sup>2</sup>SO and EG at 1.0, 2.0, 3.0, and 4.0 M for 0.25. 0.5, 1.0, 2.0, and 3.0 at room temperature. The cryoprotectants were then removed and the activities of two glycolytic enzymes, lactate dehydrogenase (LDH) and glucose-6-phosphate dehydrogenase (G-6-PDH), were determined.
Adam, M.M.; Rana, K.J.; McAndrew, B.J. Effect of Cryoprotectants on Activity of Selected Enzymes in Fish Embryos. Cryobiology (1995) 32 (1) 92-104. [DOI: 10.1006/cryo.1995.1008]