【摘要】 将巨大芽孢杆菌 (Bacillusmegaterium)胞外青霉素酰化酶通过共价键结合到聚合物载体EupergitC颗粒环氧基团上 ,制成的颗粒状固定化青霉素酰化酶表现活力达 1 40 0 μ/g左右。固定化酶水解青霉素的最适 pH8 0 ,最适温度为 55℃。在pH6 0～ 8 5、温度低于 40℃时固定化酶活力稳定。在 pH8 0、温度 37℃时 ,固定化酶对青霉素的表现米氏常数Ka为 2×1 0 - 2 mol/L ;苯乙酸为竞争性抑制剂 ,抑制常数Kip为 2 8× 1 0 - 2 mol/L ;6 APA为非竞争性抑制剂 ,抑制常数Kia为 0 1 2 5mol/L。固定化酶水解青霉素 ,投料浓度为 8% ,在使用 2 0 0批后 ,保留活力 80 %左右 ,6 APA收率平均达 89 48%。更多还原

【Abstract】 The extracellular penicillin acylase from Bacillus megaterium was immobilized on oxirane group of Eupergit C beads.The apparent activity of the immobilized enzyme was about 1400u·g -1 (dry weight).The optimal pH and temperature were 8.0 and 55℃ for hydrolytic reaction of penicillin G,respectively.The immobilized enzyme was stable in the pH range of 6.0～8.5 and at temperature below 45℃.The apparent Michaelis constant for penicillin G was inhibition constant of phenylacetic acid as competivive 2×10 -2 mol·L -1 and V m was 1.33mmol·g -1 min -1 (dry weight)at 37℃ and PH8.0.The inhibitor and 6 APA as non competitive inhibitor were 2.8×10 -2 mol·L -1 and 0.125mol·L -1 for the immobilized enzyme at pH 8.0 and 37℃,respectively.The remained activity of the immobilized enzyme was about 80% after operating 200 times for hydrolysis of penicillin G to 6 APA,and the average yield of 6 APA was 89.48%.更多还原