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为了探究影响GH5家族β-甘露聚糖酶最适pH的各种因素,利用该酶的序列信息,构建了基于氨基酸组成的β-甘露聚糖酶理化性质与其最适pH的相关性模型。结果表明:该酶N端氨基酸序列是影响其最适pH的重要因素,在243个理化性质中有17个呈极显著相关,其中7个呈正相关。优化的转移能量参数相关性最高,为0.78:7个正相关的理化性质中,与螺旋相关的理化性质占3个。优化的转移能量参数和螺旋是影响pH稳定性的最重要的因素。所建立的模型为研究该酶酸碱适应性机理提供了一种简单有效的方法。 相似文献
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β-甘露聚糖酶属于糖苷水解酶(glycoside hydrolases,GH)家族,广泛存在于植物、动物和微生物中,主要水解产物为甘露低聚糖(mannan-oligosaccharides,MOS)。微生物来源的甘露聚糖酶种类多且活性高,但大部分安全性低,其中乳酸菌(lactic acid bacteria,LAB)甘露聚糖酶具有纯化步骤少、易于提取、安全性高等优点,能够满足食品级工业生产的需求,因此在保健品、饲料、饮料生产等工业中有重要应用前景。本文介绍了天然LAB甘露聚糖酶的产酶条件、分离纯化和酶学特性,简述了近年来甘露聚糖酶的LAB重组表达及其在果汁澄清和制备益生元MOS方面的应用,为LAB甘露聚糖酶的基础研究和开发提供参考和依据。 相似文献
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β-甘露聚糖酶的基因与表达 总被引:2,自引:0,他引:2
β-甘露聚糖酶(EC 3.2.1.78)是一类能够水解含β-1,4-D-甘露糖苷键的内切水解酶,属于半纤维素酶类。水解的底物有半乳甘露聚糖、葡萄甘露聚糖、半乳葡萄甘露聚糖和甘露聚糖,产物有少量的单糖和2~10个单糖分子构成的寡糖。在纸浆漂白,饲料加工,食品加工等方面具有广阔的应用前景。文章综述了近年来国内外对β-甘露聚糖酶的基因序列、分子的结构区域、基因克隆和表达方面的研究进展。 相似文献
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β-甘露聚糖酶高产菌株发酵条件优化 总被引:5,自引:1,他引:4
从土壤中分离出1株产β-甘露聚糖酶的优良菌株Bacillus sp.QYW-1,具有发酵周期短且产酶活力高等特性,初始酶活力21.85 U/mL。在单因素实验对培养基及培养条件优化的基础上利用Plackett-Burman实验设计对影响产酶的重要因素进行筛选。实验发现,影响该菌株产酶的重要因素是魔芋粉、蛋白胨及硫酸镁。最陡爬坡实验和Box-Behnken实验得到响应面(RSM)优化的最佳培养基为:魔芋粉26 g/L,蛋白胨10 g/L,MgSO43.8 g/L,NaCl 10 g/L,KCl 6 g/L,NaNO36 g/L,K2HPO43 g/L,初始pH6.5。在此条件下菌株发酵产β-甘露聚糖酶酶活力为233.86 U/mL,与模型预测值相符,与单因素优化后的酶活力115.62 U/mL相比,提高了102%。 相似文献
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B.M. Roque G.C. Reyes T.A. Tewoldebrhan J. A. D. R.N. Apphuamy J.-J. Lee S. Seo E. Kebreab 《Journal of dairy science》2019,102(5):4198-4204
Exogenous enzymes have been used to improve nutrient utilization in several species of livestock, particularly swine and poultry. In addition, improved immunological and metabolic traits have been reported in nonruminants. The objective of this study was to determine the effects of β-mannanase supplementation on milk yield and composition, and immunological and metabolic responses in lactating Holstein dairy cows. Two weeks after calving, 20 Holstein cows (10 multiparous and 10 primiparous) were blocked by parity and assigned to 1 of 2 diets for 182 d. All cows were housed in the same environment and fed the same basal diet. The basal diet of the treatment group was supplemented with β-mannanase (CTCBio Inc., Seoul, South Korea) at 0.1% of concentrate dry matter. No differences were detected between the control and enzyme supplement groups in milk yield parameters or milk composition. Supplementation of β-mannanase enzyme reduced blood haptoglobin levels in supplemented multiparous cows compared with controls. Furthermore, nonesterified fatty acid concentration levels tended to be lower in cows fed β-mannanase, regardless of parity. Neither immunoglobulin G nor milk somatic cell count was affected by β-mannanase supplementation, regardless of parity. The number of insemination services tended to be lower in cows fed diets supplemented with β-mannanase. Results from this study suggest that supplementation of β-mannanase exogenous enzyme could help to reduce instances of systemic inflammation and decrease fat mobilization in lactating Holstein cows. Multiparous cows are considered susceptible to acute infections and inflammation; thus, the enzyme had a greater effect in multiparous cows. 相似文献
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本文以魔芋粉为碳源培养枯草芽孢杆菌S-88获得一种β-甘露聚糖酶粗酶液,粗酶液通过硫酸铵梯度盐析、超滤、HiprepTM 26/10脱盐柱脱盐、HiprepTM 16/10 DEAE FF阴离子树脂和G-75凝胶柱的纯化,该枯草芽孢杆菌S-88产的甘露聚糖酶的酶活力达到61697.52 IU/mL。用聚丙烯酰胺凝胶电泳测定纯化后酶的分子量为30 kda,比其它细菌产的β-甘露聚糖酶分子量(50 kda)小。β-甘露聚糖酶在pH 6.0和50℃的酶活性最大。它在pH 4.4~6.8之间有很好的稳定性,37℃水浴2 h酶活保持在80%以上。55℃以下水浴2 h,酶活力保持在90%以上,该酶有较好的耐热性,煮沸80 min该酶活力才能基本上消失。 相似文献