Fernández Michael, Villalonga María de Lourdes, Fragoso Alex, Cao Roberto, Villalonga Reynaldo
Enzyme Technology Group, Center for Biotechnological Studies, University of Matanzas, Matanzas, C.P. 44740, Cuba.
Biotechnol Appl Biochem. 2002 Dec;36(3):235-9. doi: 10.1042/ba20020056.
Bovine pancreatic alpha -chymotrypsin was chemically modified with two different beta -cyclodextrin derivatives, named mono-6-formyl-beta-cyclodextrin and mono-6-succinyl-6-deoxy-beta-cyclodextrin. The modified enzymes contained approx. 3-5 mol of oligosaccharide/mol of protein, and retained full proteolytic and esterolytic activity. The optimum temperature for alpha -chymotrypsin was increased by 8 degrees C and its thermostability was enhanced by about 4-6 degrees C after modification. The conjugated enzymes were also more resistant to thermal inactivation at temperatures ranging from 45 to 55 degrees C. Additionally, the modified enzymes were 7-fold more stable against incubation at pH 9.0. The possible influence of supramolecular interactions on the thermal stabilization of modified alpha -chymotrypsins was also studied.
用两种不同的β-环糊精衍生物，即单-6-甲酰基-β-环糊精和单-6-琥珀酰基-6-脱氧-β-环糊精对牛胰α-糜蛋白酶进行化学修饰。修饰后的酶每摩尔蛋白质含有约3至5摩尔的寡糖，并保留了全部的蛋白水解和酯水解活性。修饰后，α-糜蛋白酶的最适温度提高了8℃，其热稳定性提高了约4至6℃。在45至55℃的温度范围内，共轭酶对热失活也更具抗性。此外，修饰后的酶在pH 9.0条件下孵育时的稳定性提高了7倍。还研究了超分子相互作用对修饰后的α-糜蛋白酶热稳定性的可能影响。
