Tormanen C D
Department of Chemistry, Central Michigan University, Mount Pleasant 48859.
Cryobiology. 1992 Aug;29(4):511-8. doi: 10.1016/0011-2240(92)90054-6.
Polyethylene glycol is a water-soluble polymer which is widely used in the pharmaceutical, cosmetic, and chemical industries. In this study, it is shown that polyethylene glycol is an effective cryoprotectant of rat kidney transamidinase purified from both the mitochondria and cytosol. Much of the activity is lost when the purified enzyme is frozen and thawed in sodium-potassium phosphate buffer in the absence of cryoprotectants. Polyethylene glycols with molecular weights of 4000 to 10,000 were effective cryoprotectants. However, polyethylene glycols with a molecular weight of 1000 or lower inhibited the purified enzyme. A concentration of only 0.01% polyethylene glycol 4000, 8000, or 10,000 was required for complete cryoprotection. In addition to polyethylene glycol, 0.5 mM ethylenediaminetetraacetic acid was required in the phosphate buffer for complete cryoprotection. The stabilization of purified transamidinase by polyethylene glycol will facilitate characterization experiments designed to compare the properties of the mitochondrial and cytosolic isozymes.
聚乙二醇是一种水溶性聚合物，广泛应用于制药、化妆品和化学工业。本研究表明，聚乙二醇是从线粒体和胞质溶胶中纯化得到的大鼠肾脏转脒基酶的有效冷冻保护剂。在没有冷冻保护剂的情况下，将纯化的酶在磷酸钠钾缓冲液中冷冻和解冻时，大部分活性会丧失。分子量为4000至10000的聚乙二醇是有效的冷冻保护剂。然而，分子量为1000或更低的聚乙二醇会抑制纯化的酶。完全冷冻保护仅需要0.01%的聚乙二醇4000、8000或10000。除聚乙二醇外，磷酸盐缓冲液中还需要0.5 mM乙二胺四乙酸以实现完全冷冻保护。聚乙二醇对纯化的转脒基酶的稳定作用将有助于设计用于比较线粒体和胞质同工酶性质的表征实验。
