Furukawa Y, Urano T, Itoh H, Takahashi C, Kimura S
Department of Food Chemistry, Faculty of Agriculture, Tohoku University, Miyagi.
J Biochem. 1989 Jun;105(6):962-7. doi: 10.1093/oxfordjournals.jbchem.a122788.
Lecithin-cholesterol acyltransferase was purified from rat plasma and the properties of this enzyme during the purification procedures and those of the purified enzyme were investigated in comparison with the human enzyme. The rat enzyme was not adsorbed on hydroxyapatite, which was employed for the purification of the human enzyme. When purified human enzyme was incubated at 37 degrees C in 0.1 mM phosphate buffer (pH 7.4; ionic strength, 0.00025), no alteration of enzyme activity was observed for up to 6 h. In the case of the rat enzyme, however, approximately 40% of the enzyme activity was lost under the same conditions. The human enzyme and rat enzyme were both retained on a Sepharose 4B column to which HDL3 was covalently linked, in 39 mM phosphate buffer, pH 7.4. Although the human enzyme was eluted from the column in 1 mM phosphate buffer, the rat enzyme was dissociated from the column at a lower buffer concentration (0.1 mM phosphate buffer). These findings indicate that the rat enzyme effectively associated with HDL3 in 39 mM phosphate buffer, pH 7.4, but the association was more sensitive to increase of ionic strength compared with that of the human enzyme.
从大鼠血浆中纯化卵磷脂胆固醇酰基转移酶，并在纯化过程中研究该酶的性质，同时将纯化后的酶与人源酶进行比较。大鼠的酶不吸附在用于纯化人源酶的羟基磷灰石上。将纯化后的人源酶在37℃下于0.1 mM磷酸盐缓冲液（pH 7.4；离子强度，0.00025）中孵育6小时，未观察到酶活性的变化。然而，对于大鼠的酶，在相同条件下约40%的酶活性丧失。在pH 7.4的39 mM磷酸盐缓冲液中，人源酶和大鼠的酶都保留在共价连接有HDL3的琼脂糖4B柱上。虽然人源酶在1 mM磷酸盐缓冲液中从柱上洗脱，但大鼠的酶在较低的缓冲液浓度（0.1 mM磷酸盐缓冲液）下从柱上解离。这些发现表明，大鼠的酶在pH 7.4的39 mM磷酸盐缓冲液中与HDL3有效结合，但与人类酶相比，这种结合对离子强度增加更敏感。
