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壳聚糖经果糖修饰以改善其水溶性,再经半胱氨酸修饰得到巯基化果糖-壳聚糖。海藻酸钠与巯基化果糖-壳聚糖混合溶液经氯化钙及硫酸钠双重交联制得复合水凝胶珠。溶胀试验结果表明:该凝胶珠在pH值6.8及7.4时的溶胀率分别是pH值1.2时的7倍和10倍左右。牛血清白蛋白(BSA)包载试验结果表明:BSA重量为凝胶珠质量的20%时,包载率可达94%以上,随着巯基化果糖-壳聚糖在凝胶珠中比例增加,BSA包载率上升。BSA释放试验表明:pH值1.2时BSA的释放率很低,只有6%~10%的BSA从凝胶珠中释放出来,随后累积释放量基本不变;pH值6.8和pH值7.4时BSA的释放率迅速提高,因此这种复合水凝胶珠可作为一种潜在的口服蛋白类药物载体。 相似文献
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以固相酯化法制备一种具有羧基的柠檬酸改性麦草阳离子吸附剂.用批次实验法研究了不同实验条件下(pH值、吸附剂量、吸附质浓度和吸附时间)水溶液中铜离子和亚甲蓝在酯化麦草上的吸附行为.结果表明:溶液初始pH≥40时,铜离子和亚甲蓝达到最大吸附值.≥2.0 g·L-1的酯化麦草能去除铜浓度为100 mg·L-1溶液中96%的铜及亚甲蓝浓度为250 mg·L-1溶液中99%的亚甲蓝.酯化麦草对铜离子和亚甲蓝的吸附符合Langmuir等温模型,其最大吸附能力分别为79.37 mg·g-1和312.50 mg·g-1.铜离子和亚甲蓝达到吸附平衡的时间分别为75 min和5 h,准一级和准二级反应动力学方程可分别描述酯化麦草对铜离子和亚甲蓝的吸附过程. 相似文献
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吡啶核苷酸转氢酶(pyridine nucleotide transhydrogenases)是能直接催化NADP(H)与NAD(H)之间氢负离子可逆转移的氧化还原酶, 主要调控分解代谢和合成代谢过程中NADH与NADPH之间的动态平衡. 膜结合吡啶核苷酸转氢酶(TH)是ATP依赖性跨膜蛋白, 由2个亚基构成, 每个亚基包含dⅠ、dⅡ和dⅢ三个结构域. 在TH结合可变催化机制中, 氢负离子的转移总是与质子转移相偶联. 可溶性吡啶核苷酸转氢酶(STH)是非能量依赖性的黄素蛋白, 以可溶性多聚体形式存在. 目前认为,很多因活性氧自由基异常增多而引起的线粒体疾病都与TH的活性有关, 包括糖尿病、癌症、神经退行性疾病及心血管疾病等. TH分子机制的研究将有助于揭示这些线粒体疾病的致病机理以及为其诊断和基因治疗提供分子依据. STH作用机理的研究及其在辅酶再生系统中的应用, 将会推动代谢工程和工业生物催化过程的进一步发展. 相似文献
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花生壳粉生物吸附水溶液中阴离子染料的研究 总被引:1,自引:1,他引:0
An untried,low cost, locally available biosorbent for its anionic dye removal capacity from aqueous solution was investigated. Powder prepared from peanut hull had been used for hiosorption of three anionic dyes, amaranth (Am), sunset yellow (SY) and fast green FCF (FG). The effects of various experimental parameters (e.g.initial pH and dye concentration, sorbent dosage, particle size, ion strength, contact time etc.) were examined and optimal experimental conditions were decided. At initial pH 2.0, three dyes studied could be removed effectively.When the dye concentration was 50 mg" L-1 the percentages of dyes sorbed was 95.5 % in Am, 91.3 % in SY and 94.98 % in FG, respectively. The ratios of dyes sorbed had neared maximum values in all three dyes whensorbent dose of 5.0 g·L^-1 and the sorbent particle size in 80—100 mesh was used. The increasing the ion strength of solution caused the decrease in biosorption percentages of dyes. The equilibrium values arrived at about 36 hour for all three dyes. The isothermal data of biosorption followed the Langmuir and Freundlich models. The biosorption processes conformed the pseudo-first-order rate kinetics. The results indicated that powdered peanut hull was an attractive candidate for removing anionic dyes from dye wastewater. 相似文献
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