Koch-Schmidt A C, Mosbach K
Biochemistry. 1977 May 17;16(10):2105-9. doi: 10.1021/bi00629a009.
Ribonuclease A (EC 3.1.4.22) and alpha-chymotrypsin (EC 3.4.21.1) have been covalently coupled, by a varying number of bonds, to Sepharose CL 4B which was activated with different amounts of CNBr. Upon increasing the number (1-8) of points of attachment between the enzyme and the matrix, the specific activities of immobilized ribonuclease A relative to its soluble counterpart decreased from 60 to 15% while the amount of protein coupled increased from 5 to 37 mg per g of sucked gel. Differential scanning calorimetry was used to determine whether the immobilization caused any changes in the physicochemical properties of the enzyme. Ribonuclease A, weakly bound to the matrix, showed almost the same behavior as the soluble enzyme. By contrast strongly immobilized enzyme exhibited a higher transition temperature (by about 5 degrees C) and a broader endotherm. Similar results were found for alpha-chymotrypsin.
核糖核酸酶A（EC 3.1.4.22）和α-胰凝乳蛋白酶（EC 3.4.21.1）已通过不同数量的化学键与用不同量溴化氰活化的琼脂糖凝胶CL 4B共价偶联。随着酶与基质之间连接点数量（1至8个）的增加，固定化核糖核酸酶A相对于其可溶性对应物的比活性从60%降至15%，而每克吸附凝胶偶联的蛋白质量从5毫克增加到37毫克。采用差示扫描量热法来确定固定化是否会引起酶的物理化学性质发生任何变化。与基质弱结合的核糖核酸酶A表现出与可溶性酶几乎相同的行为。相比之下，强固定化的酶表现出更高的转变温度（约高5摄氏度）和更宽的吸热峰。α-胰凝乳蛋白酶也得到了类似的结果。
