中文摘要：

采用1,6-己二胺对烟酰胺辅酶（NADH）的腺嘌呤C8位点进行定点修饰，通过DEAE—Sepharose层析分离得到产物8-（6-氨基己烷）-氨基-NADH．经优化制备过程和分离条件，其收率可达60％．在pH2．2-8．0内系统考察了修饰产物的pH稳定性，结果表明在不同种类的缓冲液中，修饰后辅酶的稳定性均有显著提高，在pH6．5的柠檬酸盐和pH8．0的磷酸盐缓冲液中，半衰期分别延长11和5倍．通过利用乳酸脱氢酶（LDH）和谷氨酸脱氢酶（GDH）测定修饰前后辅酶的活性，发现相同反应条件下修饰后辅酶的反应速率分别是天然NADH的3．0-3．8倍（LDH）和1．3-1．4倍（GDH）．

英文摘要：

8-（6-aminohexyl）-amino-NADH was successfully prepared by modifying NADH with 1,6-hexanediamine at the C8 position of adenine moiety. After 3-step synthesizing process, the product was purified on DEAE-Sepharose column with the final yield up to 60%. The stability of NH2（CH2）6NH-NADH in acid or neutral environment was studied and compared with the native NADH. The results showed that the modified NADH was more stable than the native one, particularly in the citric acid-sodium citrate buffer （pH 6.5） and phosphate buffer （pH 8.0）, the half life of modified NADH increased 11.0 folds and 5.0 folds, respectively. Catalytic activity of the modified NADH was evaluated with lactate dehydrogenase （LDH） and glutamate dehydrogenase （GDH） systems. For LDH and GDH, the activity for NH2（CH2）6NH-NADH was 3.0-3.8 or 1.3-1.4 times higher than that of native NADH, respectively.