固定化青霉素G酰化酶水解头孢菌素G制备7—ADCA的研究

THE HYTROLYSIS OF CEPHALOSPORIN G TO 7 - AMINODEA CETOXY - CEFALOSPORANIC ACID BY IMMOBILIZED PENICILLIN ACYLASE

用聚丙烯腈纤维固定化青霉素酰化酶水解头孢菌素G制备7-ADCA,固定化酶对头孢菌素G的最适pH为9.0,最适温度50℃。在37℃、pH8.0固定化酶对头孢菌素G的表观米氏常数为1.67×10^(-2)mol/L。最大反应速度为3.01mmol·g^(-1)·min^(-1)。头孢菌素G溶液浓度在2％以上时,对固定化酶有明显的抑制作用。固定化酶水解头孢菌素G的最佳投料浓度为5％～6％,水解时用酶量以每克头孢菌素G投300U以上为好。按上述条件水解头孢菌素G,操作25批后固定化酶保留活力77.8％,7-ADCA平均收率92.68％。

The extracellular penicillin G acylase (PA) from Bacillus megaterium was immobilized on polyacrylonnitrile fibres by coupling. The optimal pH and temperature values of the immobilized penicillin acylase (IMPA) for the hydrolysis cephalosporin G (cep G) was 9.0 and 50 ℃ respectively, the apparent Michaelis constant for Cep G was l.67×10-2mol /L and the Vm was 3-01 rnmol·g-1 · min-1 at 37 ℃ pH 8.0. It is good for hydrolysis of cephalosporin G, the 5% -6% concentration of cefalosporin G and the 300U activity of the IMPA for one gram cephalosporin G was used. The remained activety was 77.8% after operation 25 times and the yield of 7-ADCA was 92.68%.