Weiss B, Hui M, Lajtha A
Res Commun Chem Pathol Pharmacol. 1979 Jul;25(1):153-64.
The best from a series of matrices for the covalent coupling of rat liver phenylalanine (Phe H) was activated thiol-Sepharose 4B. An average of 0.38 mumoles of enzyme thiol was coupled per mumole of matrix thiol, representing 21 mg of protein per g of carrier. After thiolation with N-acetylhomocysteine thiolactone the enzyme, bound to the same matrix, was thermally more stable with a broad pH range of optimal activity. Thiolation with S-acetylmercaptosuccinic anhydride markedly reduced hydroxylase activity whereas succinylation with succinic anhydride had little or no effect. Treatment of the thiolated enzyme with various oxidants to form disulfide bridges did not increase the thermal stability. Efforts to improve stability by formation of new linkages while the enzyme was still bound to the matrix were unsuccessful. The untreated or thiolated enzyme was inactivated upon reaction with glutaraldehyde.
用于大鼠肝脏苯丙氨酸（Phe H）共价偶联的一系列基质中，最佳的是活化硫醇-琼脂糖4B。每微摩尔基质硫醇平均偶联0.38微摩尔酶硫醇，相当于每克载体结合21毫克蛋白质。用N-乙酰高半胱氨酸硫内酯进行硫醇化后，结合在同一基质上的酶热稳定性更高，且具有较宽的最佳活性pH范围。用S-乙酰巯基琥珀酸酐进行硫醇化显著降低了羟化酶活性，而用琥珀酸酐进行琥珀酰化作用很小或没有影响。用各种氧化剂处理硫醇化酶以形成二硫键并没有提高热稳定性。在酶仍结合在基质上时，通过形成新键来提高稳定性的尝试未成功。未处理或硫醇化的酶与戊二醛反应后会失活。
