以赖氨酸（Lys）修饰阳离子交换树脂D155合成出赖氨酸修饰两性阳离子交换树脂（Lys-D155）,再以该树脂为载体,制备出固定化腈水解酶（I-Nit-D155）,最后以I-Nit-D155为催化剂水解R,S-扁桃腈研究制备固定化腈水解酶的优化条件、主要酶学...以赖氨酸（Lys）修饰阳离子交换树脂D155合成出赖氨酸修饰两性阳离子交换树脂（Lys-D155）,再以该树脂为载体,制备出固定化腈水解酶（I-Nit-D155）,最后以I-Nit-D155为催化剂水解R,S-扁桃腈研究制备固定化腈水解酶的优化条件、主要酶学性质并对水解产物进行表征。红外分析表明,经赖氨酸修饰的D155成功制备出固定化腈水解酶I-Nit-D155。制备I-Nit-D155的优化条件为：室温、p H 5.25、载体游离氨基/戊二醛/腈水解酶摩尔比1∶0.11∶2.12×10-4,I-Nit-D15活力为10~15 U/mg、偶联率43.2%、Km值23.11 mmol/L,重复使用15次后活力仍可保持50%以上;I-Nit-D15水解R,S-扁桃腈的产物的熔点、比旋光度等分别为133℃、-155.57°,与R-扁桃酸一致,经红外、1H-和13C-核磁共振波谱表征确证为R-扁桃酸。展开更多
N-acetyl-glucosamine, the monomer of chitin, was cyclo-condensed with L-cysteine to prepare thiazolidine derivative： 2-N-acetyl-glucosamine-thiazolidine-4（R）-carboxylic acid （GlcNAcCys）. The stability of GlcNAcCy...N-acetyl-glucosamine, the monomer of chitin, was cyclo-condensed with L-cysteine to prepare thiazolidine derivative： 2-N-acetyl-glucosamine-thiazolidine-4（R）-carboxylic acid （GlcNAcCys）. The stability of GlcNAcCys was evaluated by high performance liquid chromatography （HPLC） measurement. The results showed that GlcNAcCys was more stable than other TCA derivatives, especially in alkaline condition. The direct in vitro antioxidative properties of GlcNAcCys were investigated by using UV radiation-induced lipid peroxidation （LPO） in mitochondria and nuclei and . OH-induced LPO in red blood cell （RBC） ghosts models. UV radiation caused dose-dependent LPO in both mitochondria and nuclei. This effect was catalyzed by addition of Fe^2 ＋ while prevented by co-incubation with GlcNAcCys. When nuclei and mitochondria was treated with 100μl, 300μl, 500μl of GlcNAcCys and co-incubated at 37℃ for 30min, LPO was decreased to 96%, 72%, 68% in nuclei and 95%, 72%, 68% in mitochondria when compared to the UV radiation group respectively. Hydroxyl radicals （. OH） generated by Fenton reaction induced LPO in RBC ghosts. Pretreatment of RBC ghosts with GlcNAcCys could induce antioxidant RBC ghosts and inhibit concentration-dependent malondialdehyde （MDA） formation in antioxidant RBC ghosts. Its inhibition percent was 14%, 35%, 36%, 42% at 10, 20, 30, 40mg/ml respectively. In a conclusion, the data suggest that GlcNAcCys has antioxidant ability and can significantly inhibit lipid peroxidation in biological samples tested in vitro.展开更多
文摘以赖氨酸（Lys）修饰阳离子交换树脂D155合成出赖氨酸修饰两性阳离子交换树脂（Lys-D155）,再以该树脂为载体,制备出固定化腈水解酶（I-Nit-D155）,最后以I-Nit-D155为催化剂水解R,S-扁桃腈研究制备固定化腈水解酶的优化条件、主要酶学性质并对水解产物进行表征。红外分析表明,经赖氨酸修饰的D155成功制备出固定化腈水解酶I-Nit-D155。制备I-Nit-D155的优化条件为：室温、p H 5.25、载体游离氨基/戊二醛/腈水解酶摩尔比1∶0.11∶2.12×10-4,I-Nit-D15活力为10~15 U/mg、偶联率43.2%、Km值23.11 mmol/L,重复使用15次后活力仍可保持50%以上;I-Nit-D15水解R,S-扁桃腈的产物的熔点、比旋光度等分别为133℃、-155.57°,与R-扁桃酸一致,经红外、1H-和13C-核磁共振波谱表征确证为R-扁桃酸。
文摘N-acetyl-glucosamine, the monomer of chitin, was cyclo-condensed with L-cysteine to prepare thiazolidine derivative： 2-N-acetyl-glucosamine-thiazolidine-4（R）-carboxylic acid （GlcNAcCys）. The stability of GlcNAcCys was evaluated by high performance liquid chromatography （HPLC） measurement. The results showed that GlcNAcCys was more stable than other TCA derivatives, especially in alkaline condition. The direct in vitro antioxidative properties of GlcNAcCys were investigated by using UV radiation-induced lipid peroxidation （LPO） in mitochondria and nuclei and . OH-induced LPO in red blood cell （RBC） ghosts models. UV radiation caused dose-dependent LPO in both mitochondria and nuclei. This effect was catalyzed by addition of Fe^2 ＋ while prevented by co-incubation with GlcNAcCys. When nuclei and mitochondria was treated with 100μl, 300μl, 500μl of GlcNAcCys and co-incubated at 37℃ for 30min, LPO was decreased to 96%, 72%, 68% in nuclei and 95%, 72%, 68% in mitochondria when compared to the UV radiation group respectively. Hydroxyl radicals （. OH） generated by Fenton reaction induced LPO in RBC ghosts. Pretreatment of RBC ghosts with GlcNAcCys could induce antioxidant RBC ghosts and inhibit concentration-dependent malondialdehyde （MDA） formation in antioxidant RBC ghosts. Its inhibition percent was 14%, 35%, 36%, 42% at 10, 20, 30, 40mg/ml respectively. In a conclusion, the data suggest that GlcNAcCys has antioxidant ability and can significantly inhibit lipid peroxidation in biological samples tested in vitro.
