Öztop Hesna N, Akyildiz Furkan, Saraydin Dursun
Biochemistry Department, Faculty of Science, Sivas Cumhuriyet University, Sivas, Turkey.
Chemistry Department, Faculty of Science, Sivas Cumhuriyet University, Sivas, Turkey.
Microsc Res Tech. 2020 Dec;83(12):1487-1498. doi: 10.1002/jemt.23542. Epub 2020 Jul 28.
Poly (acrylamide/vinylsulfonic acid) PA/VSA and poly (acrylamide) PA hydrogels were prepared by free radical polymerization in the presence of a crosslinker, to be used as a support for the invertase enzyme. Spectrophotometric, thermal analysis methods, swelling, and diffusion experiments were used for the characterization of hydrogels. SEM images show that the hydrogels have a smooth, homogeneous, highly porous and spongy morphology. The swelling of PA/VSA was higher than that of PA in water. The diffusion of water within the hydrogel was found to be non-Fickian. Invertase was immobilized onto PA and PA/VSA (immobilized invertases named PA-I and PA/VSA-I, respectively). The optimum pH values were found to be; 5.0, 3.0, and 3.0 for free invertase, PA-I, and PA/VSA-I, respectively. The optimum temperature values were 40°C, 50°C, and 60°C for free invertase, PA-I and PA/VSA-I respectively. Michaelis Constant, K ; for free invertase and PA-I and PA/VSA-I were found to be 11.80, 21.40, and 18.42 mM, respectively. Maximum reaction rate; V value for free invertase and PA-I and PA/VSA-I were found to be 7.46 μmol min , 5.91 μmol min , and 6.35 μmol min , respectively. PA/VSA-I showed excellent thermal, operational, storage, and pH stability.
通过在交联剂存在下进行自由基聚合制备了聚（丙烯酰胺/乙烯基磺酸）PA/VSA和聚（丙烯酰胺）PA水凝胶，用作转化酶的载体。采用分光光度法、热分析方法、溶胀和扩散实验对水凝胶进行表征。扫描电子显微镜图像显示，水凝胶具有光滑、均匀、高度多孔且呈海绵状的形态。PA/VSA在水中的溶胀度高于PA。发现水在水凝胶内的扩散是非菲克扩散。将转化酶固定在PA和PA/VSA上（固定化转化酶分别命名为PA-I和PA/VSA-I）。发现最佳pH值分别为：游离转化酶为5.0，PA-I为3.0，PA/VSA-I为3.0。最佳温度值分别为：游离转化酶为40°C，PA-I为50°C，PA/VSA-I为60°C。游离转化酶、PA-I和PA/VSA-I的米氏常数Km分别为11.80、21.40和18.42 mM。最大反应速率；游离转化酶、PA-I和PA/VSA-I的V值分别为7.46 μmol min、5.91 μmol min和6.35 μmol min。PA/VSA-I表现出优异的热稳定性、操作稳定性、储存稳定性和pH稳定性。
