Zagrebel'nyĭ S N, Oreshkova S F
Prikl Biokhim Mikrobiol. 1987 May-Jun;23(3):303-8.
Preparations of alkaline phosphatase from E. coli, immobilized on Sepharose, with a specific activity of 40-60 U/g wet weight were obtained. The immobilized enzyme was stable up to 50 degrees C; at higher temperatures it was inactivated. At 70 degrees most of the activity was lost for 1 h. The substrate (AMP) stabilized the enzyme. In the temperature range from 30 to 40 degrees C activation of the enzyme was observed, especially pronounced in the presence of the substrate. The pH optimum of the immobilized enzyme activity (7.8-8.2) is shifted towards the acid region, as compared to the soluble enzyme (8.0-8.6). The kinetic parameters for inhibition by the reaction product were determined using the integral Michaelis-Menten equation. KmAMP was found to be higher in case of the immobilized enzyme as compared to the soluble one (5.02 X 10(-4) M and 1.85 X 10(-5) M, respectively), which seems to be associated with diffusion limitations.
获得了固定在琼脂糖上的大肠杆菌碱性磷酸酶制剂，其比活性为40 - 60 U/g湿重。固定化酶在高达50℃时稳定；在较高温度下会失活。在70℃时，1小时内大部分活性丧失。底物（AMP）使酶稳定。在30至40℃的温度范围内观察到酶的活化，在底物存在下尤为明显。与可溶性酶（8.0 - 8.6）相比，固定化酶活性的最适pH（7.8 - 8.2）向酸性区域偏移。使用积分米氏方程测定了反应产物抑制的动力学参数。发现固定化酶的KmAMP比可溶性酶更高（分别为5.02×10⁻⁴ M和1.85×10⁻⁵ M），这似乎与扩散限制有关。
