球孢白僵菌胞外壳聚糖酶的纯化和性质

球孢白僵菌Beauveria bassiana 1316-V1的培养上清液经硫酸铵分级沉淀,SephadexG-75凝胶过滤,Chitosan-bead亲和层析,第二次SephadexG-75凝胶过滤,得到电泳纯的一种胞外壳聚糖酶,比活力达到45u/mg。此酶的分子量为36kD;最适酶反应温度为60℃;最适pH为4.0;最适离子强度为0.25mol/LNaCl;37℃以下,pH2.0-5.0之间稳定性好;Cu^2 ,Hg^2 ,Pb^2 ,Ni^2 对该酶有强烈抑制作用;Ag^ ,Mn^2 也有较强抑制作用;Fe^2 有轻微激活作用,该壳聚糖酶是一种糖蛋白,含糖约为12.6%。酶的最适底物为脱乙酰度为90%的胶体壳聚糖;也能轻微水解CMC、DEAE-Cellulose和胶体几丁质;但不能水解片状的壳聚糖和几丁质。     

烟草磷酸吡哆醛水解酶的分离纯化与表征

采用硫酸铵沉淀、DEAE-Sepharose Fast Flow阴离子交换、Sephadex G-100凝胶过滤和SP Sephadex C-25阳离子交换柱层析等步骤,对烟草磷酸吡哆醛水解酶进行了分离纯化。结果表明:该酶被纯化了119.6倍,得率为28.49%,经凝胶过滤和SDS-PAGE测得该酶的全分子量为49.6kDa,亚基分子量约为25kDa;该酶最适温度为50℃,最适反应pH为5.5;Mg2+、Ca2+、Mn2+等对该酶有激活作用,金属离子螯合剂EDTA对酶有抑制作用,加入Mg2+后抑制作用得到解除;在最适反应条件下,测得反应底物磷酸吡哆醛(PLP)和磷酸吡哆胺(PMP)的Km值分别为0.23mmol/L和0.56mmol/L。     

昆虫来源的几丁质酶的分离纯化及酶学性质

几丁质酶在真菌和昆虫的生理和发育过程中起着关键作用,该酶本身及其酶抑制剂是获取生物农药的重要途径。本研究从蚕蛹体内提取几丁质粗酶,经硫酸铵分级沉淀和Sephadex G-150分离得到几丁质酶。用SDS-PAGE测得该酶的分子量为88kDa。水解胶体几丁质的Km值为22.3μmol/L。酶反应的最适温度为45℃,最适pH值为6.0,金属离子和有机试剂对几丁质酶活性都有影响,其中高浓度的Mn2+对酶有较强的激活作用,而Cu2+、SDS则有较强的抑制作用。研究结果为基于几丁质酶的生物农药筛选研究奠定了基础。     

链霉菌壳聚糖酶的纯化及其酶学性质

分离纯化从烟台近海土壤筛选的链霉菌来源壳聚糖酶,并对其酶学性质进行研究。通过(NH4)2SO4分级沉淀分离得粗酶,透析后经Sephadex G-100柱纯化,得到2种壳聚糖酶(ChA和ChB)。SDS-聚丙烯酰胺凝胶电泳及Sephadex G-75凝胶过滤确定ChA的相对分子质量,研究ChA的最适底物水解条件、热稳定性、水解动力学及金属离子对酶活性影响。结果表明:ChA为单亚基蛋白,相对分子质量为4.16×104,在220和280 nm处呈现两个紫外吸收峰,催化水解壳聚糖的最适pH为5.0～5.5,最适温度为55℃。热稳定性实验表明:30℃温育1 h后酶活为初始酶活的33.3%,40℃温育1 h后酶活为初始酶活的22.2%。ChA的酶促反应初速率为6.2×10-3μmol/(mL.min),Vmax为0.318μmol/(mL.min),Km为1×10-2mg/mL,且对底物表现相对专一性。K+、Na+、Li+、Mg2+、Ca2+、Ba2+Zn2+、Cu2+和Co2+对ChA活力均表现为抑制作用,过渡金属离子Mn2+对酶有激活作用,重金属离子Hg2+、Ag+、Cd2+和Pb2+对酶均有较强的抑制作用。Mn2+和Zn2+的动力学研究表明,Mn2+对酶为混合型激活作用,Zn2+对酶为竞争性抑制作用。     

重组磷脂酰丝氨酸合成酶的分离纯化及酶学性质研究

利对重组枯草芽孢杆菌(pBES-pss)表达的磷脂酰丝氨酸合成酶进行分离纯化及酶学性质研究.pBES-pss发酵后的粗酶液经硫酸铵盐析、中空纤维膜除盐浓缩、SP-Sepharose HP离子交换层析和Sephadex G-75凝胶层析,基本获得电泳纯的重组磷脂酰丝氨酸合成酶,比活力可达13.62 U/mg,分子量约为53 kD.酶学性质研究表明,该酶催化卵磷脂水解反应的最适pH8.0,最适温度为35℃.稳定性研究表明:该酶在pH 6.5～9.5 区间和低于45℃温度下稳定.表面活性剂及金属离子对该酶水解活性的影响结果表明,SDS、Tween20、Tween80对该酶有抑制作用,Triton X-100对该酶有增强作用;Mg2+、Zn2+、K+对该酶有抑制作用,Ca2+、Mn2+和EDTA对该酶有增强作用.     

产气肠杆菌几丁质酶的分离纯化及性质研究

从自然罹病死亡的草原毛虫(Gynephorap ruoergnesis)体内分离到一株产气肠杆菌(Enterobacter aerogenes),它在几丁质的诱导下能产生较高活性的几丁质酶。发酵液经硫酸铵盐析、DEAE纤维素柱层析和Sephadex G-100柱层析分离出几丁质酶。用SDSPAGE测得该酶的分子量为425kD。水解几丁质的Km值为2.88mg/mL-1。酶反应的最适温度为55℃,最适pH值为60,金属离子对几丁质酶活性影响较大,其中Zn2+、Ba2+、Ca2+和Mn2+对酶有较强的激活作用,而Hg2+、Co2+和Mg2+则有较强的抑制作用。     

黄杆菌(Flavobacterium sp.)几丁质酶的纯化和性质

黄杆菌(Flavobacteium sp.)在几丁质的诱导下产生几丁质酶.通过(NH_4)_2SO_4沉淀、DEAE纤维素柱层析、Sephacryl 300柱层析及Sephadex G-75柱层析,从Flavobacterium sp.培养上清液中分离纯化了几丁质酶.SDS-聚丙烯酰胺凝胶电泳(SDS-PAGE)纯度分析表明,纯化后的几丁质酶达到了均一的程度.用SDS-PAGE测得该酶的分子量约45D00道尔顿.该酶水解几丁质的最适pH为 7.0,最适温度为50℃,-20C贮存两年以上仍有活性.水解几丁质的Km值为5.0mg/ml.金属离子对几丁质酶活性影响较大,Ca^(2+) 、Co^(2+)’和Cu^(2+)对酶有激活作用.而NH_4^-、Ba^(2+)、Mg^(2+)、Mn^(2+)对酶有抑制作用.几丁质酶水解几丁质的产物是几丁质二糖.     

根霉α-半乳糖苷酶的三相分离及其酶学性质

根霉Rhizopus sp. A01发酵豆渣产α-半乳糖苷酶,粗酶液依次经过三相分离、Sephadex G-100凝胶过滤获得了电泳纯的α-半乳糖苷酶,纯化了6.7倍,总酶活回收率达到46%;凝胶过滤和SDS-PAGE显示该酶为相对分子质量为87.6kDa的单体蛋白。该酶水解对硝基苯-α-D-吡喃半乳糖苷的最适pH值为5.0,最适温度为55℃,表观Km、kcat/Km分别为2.56mmol/L、47,400L/mol·s;能微弱水解蜜二糖和棉子糖,水解蜜二糖的速率是水解棉子糖速率的3.4倍;水解活性受多种     

球孢白僵菌胞内几丁质酶的分离纯化及性质

球孢白僵菌(Beauveria bassiana)突变株CH-1316细胞裂解液经(NH_4)_2SO_4沉淀,DEAE-纤维素层析及凝胶过滤,分离出一种几丁质酶,该酶的分子量为32000;最适pH为5.0;最适温度为40℃;最适离子强度为0.2mol/L NaCl;Hg²⁺、Fe²⁺是该酶的强抑制剂;该几丁质酶完全不水解纯的片状几丁质,脱矿几丁质也不是该酶的良好底物;该几丁质酶水解几丁寡糖,但不水解几丁二糖;对几丁五糖以上的寡糖水解速度较快,而对几丁三糖和四糖水解速度则慢得多。     

木霉GXC产β-葡聚糖酶条件和酶学性质

研究了木霉GXC产β-葡聚糖酶的条件.结果表明,最适产酶碳源为麸皮,氮源为硫酸铵;产酶的最适条件为初始pH为4.0～5.0,30℃培养44h.粗酶液经硫酸铵沉淀、Sephadex G-25、Sephadex G-100和DEAE-Sehadex A-50柱层析得到纯β-葡聚糖酶,SDS-PAGE凝胶电泳显示一条带,测得分子量为35kD.该酶最适反应pH5.0,最适反应温度为60℃,在40℃以下、pH4.0～5.0酶活力相对稳定.5.0mmol/L以下的Ca2+、Zn2+和Fe2+,以及10.0mmol/L以下的Co2+对酶活力有激活作用;而Cu2+和Fe3+具有抑制作用.     

Production, purification, and characterization of an extracellular chitosanase from Streptomyces.

The synthesis by Streptomyces sp. no. 6 of an extracellular chitosanase was induced by glucosamine. The enzyme was purified to homogeneity by Sephadex G-100, carboxymethyl-cellulose, and diethylaminoethyl-cellulose chromatography. The purified enzyme hydrolyzed chitosan (the beta-1,4-linked polymer of glucosamine) but not chitin nor carboxymethyl-cellulose. The only products of the hydrolysis detectable by paper chromatography were di- and triglucosamine. Sephadex G-100 chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that the molecular weight of the enzyme was between 29,000 and 26,000. Acid hydrolysates of the enzyme contained no cysteic acid or glucosamine or other carbohydrate. At 25 C, maximum activity was obtained between pH 4.5 and 6.5. The enzymatic hydrolysis of chitosan occurred over a wide range of temperatures and was maximal at 60 C. The rate of the reaction was inhibited by concentrations of soluble chitosan higher than 0.5 g/liter. The apparent Km calculated from a Lineweaver-Burke plot was 0.688 g/liter at pH 5.5. The enzyme prevented spore germination and caused a significant decrease in the turbidity of germinated spore suspensions of the Mucor strains tested. Such a decrease was the result of a partial lysis of the cell wall.     

来自拟青霉属真菌的壳聚糖酶的分离纯化、理化性质及降解产物的分析(英文)

从来自拟青霉属真菌Paecilomyces sp.CS-Z的发酵液中获得一种壳聚糖酶,该酶被纯化了9.4倍,产率为48.2%。经SDS-PAGE分析确定为单一条带,分子量为29kDa,其最适pH为6.0–6.5,最适温度为55℃,在80℃处理60min后,能保持较好的热稳定性,Hg2+完全抑制了酶活,对脱乙酰度85%–95%的壳聚糖具有较高的水解活性,而对几丁质和羧甲基纤维素无活性。薄层层析和质谱分析表明该酶是一种内切酶,其水解产物为聚合度大于6的壳寡糖,其理化性质与至今报道的壳聚糖酶有所不同,为壳聚糖酶的开发提供了重要的实验依据。     

绿色糖单孢菌木聚糖酶的分离纯化与酶学性质研究

木聚糖酶是一种重要的具有工业应用前景的木聚糖降解酶,在充分利用自然资源、保护生态环境等方面具有十分重要的意义.通过硫酸铵分级沉淀及Sephadex G-100凝胶柱层析方法从一株中度耐热耐碱放线菌—绿色糖单孢菌的胞外酶中纯化得到单一的木聚糖酶,相对分子质量为51 kD,酶纯度提高了13.01倍.纯酶最适反应温度为60℃,最适反应pH值为7.0;75℃以下该酶具有良好的热稳定性,在pH 7～10范围内具有较强的耐受力.金属离子Ca2+、Fe2+、Zn2+对该酶具有明显促进作用,Cu2+、Mn2+、Al3+和SDS具有抑制作用而K+,Na+,Mg2+没有明显的作用.该酶为大分子质量的糖基化蛋白,含糖量为21.96%.     

Purification and characterization of a collagenase from the mackerel,Scomber japonicus

Collagenase from the internal organs of a mackerel was purified using acetone precipitation, ion-exchange chromatography on a DEAE-Sephadex A-50, gel filtration chromatography on a Sephadex G-100, ion-exchange chromatography on DEAE-Sephacel, and gel filtration chromatography on a Sephadex G-75 column. The molecular mass of the purified enzyme was estimated to be 14.8 kDa by gel filtration and SDS-PAGE. The purification and yield were 39.5-fold and 0.1% when compared to those in the starting-crude extract. The optimum pH and temperature for the enzyme activity were around pH 7.5 and 55 degrees, respectively. The K(m) and V(max) of the enzyme for collagen Type I were approximately 1.1mM and 2,343 U, respectively. The purified enzyme was strongly inhibited by Hg2+, Zn2+, PMSF, TLCK, and the soybean-trypsin inhibitor.     

Isolation and purification of Mucor circinelloides intracellular chitosanolytic enzymes

This study aimed at isolation, purification and characterization of a chitosanase from Mucor circinelloides mycelium. The latter contains also a mycelium-bound lipase and lipids. The chitosanase and lipase were extracted from defatted M. circinelloides mycelium with a detergent and purified through a two-step procedure comprising chromatography on bacitracin–CNBr-Sepharose 4B and gel filtration on Sephadex G-100. Purification degree of the chitosanase (endo-type enzyme) and lipase was 23 and 12, respectively. These enzymes were optimally active at pH of 5.5–6.0 (chitosanase) and 7.2 (lipase in olive oil hydrolysis) and at 37 °C. Both purified enzymes were activated by Ca²⁺ and Mg²⁺ ions. The preferred substrates of chitosanase were chitosan preparations with a high degree of deacetylation. This enzyme showed no activity for colloidal chitin, Na-CMC and starch. SDS–PAGE of both purified enzymes showed two bands with molecular masses of 42 and 43 kDa. Our results suggest that M. circinelloides synthesizes an oligomeric (bifunctional) lipase which also efficiently depolymerizes chitosan.     

粘质赛氏菌胞外蛋白酶的提取、纯化及部分性质研究

经过硫酸铵３０％～５０％分级沉淀、二步柱层析可获聚丙烯酰胺凝胶电泳均一的粘质赛氏菌胞外蛋白酶制品,收率可达５３％,并制备了酶的结晶,该酶以ＳｅｐｈａｄｅｘＧ１００柱层析及ＳＤＳ－ＰＡＧＥ测得分子量约为８１０００,该酶的最适ｐＨ为７．０,最适温度为４５℃,Ｚｎ２＋、Ｍｎ２＋、Ｆｅ２＋、Ｃｕ２＋、Ｃｏ２＋等重金属离子不同程度地抑制酶活性。     

β-葡聚糖酶的分离纯化和特性研究*

对里氏木霉所产β-葡聚糖酶粗酶液通过饱和硫酸铵沉淀、Sephadex G-100 柱层析和DEAE-Sephadex A-50 柱层析进行纯化,比活提高14.60倍,活力回收6.62%。酶特性研究表明,最适温度和pH分别为60℃和5.0,在pH低于5.0时酶较稳定,酶的热稳定性在60℃以下。 Cu～2+、 Mn～2+ 、Mg～2+ 、Fe～3+ 和K+对酶有抑制作用, Zn～2+、Ca～2+、 Co2+和 Fe～2+ 有激活作用。     

β-葡聚糖酶的分离纯化和特性研究

对里氏木霉所产β-葡聚糖酶粗酶液通过饱和硫酸铵沉淀、Sephadex G-100 柱层析和DEAE-Sephadex A-50 柱层析进行纯化,比活提高14.60倍,活力回收6.62%。酶特性研究表明,最适温度和pH分别为60℃和5.0,在pH低于5.0时酶较稳定,酶的热稳定性在60℃以下。 Cu～2+、 Mn～2+ 、Mg～2+ 、Fe～3+ 和K+对酶有抑制作用, Zn～2+、Ca～2+、 Co2+和 Fe～2+ 有激活作用。     

Purification and hydrolytic action of a chitosanase from Nocardia orientalis

Chitosanase from the culture filtrate of Nocardia orientalis was purified to apparent homogeneity by precipitation with ammonium sulfate followed by CM-Sephadex chromatography, biospecific affinity chromatography on a Sepharose CL-4B with immobilized chitotriose and by gel filtration on Sephadex G-75. The enzyme specifically acted on chitooligosaccharides and chitosan to yield chitobiose and chitotriose as final products. The mode of action of the chitosanase on chitooligosaccharides and their corresponding alcohols suggests that the enzyme requires substrates with four or more glucosamine residues for the expression of activity and its shows maximum activity on chitohexaose and chitoheptaose. In the hydrolysis of chitosans of varying N-acetyl content, the enzyme cleaved about 30% acetylated chitosan with maximum activity and the enzyme activity decreased with increasing the degree of deacetylation of chitosans tested. The analysis of products formed from 33% acetylated chitosan shows the chitosanase is capable of cleaving between glucosamine and glucosamine or N-acetylglucosamine, but not cleaving between N-acetylglucosamine and glucosamine. On the basis of the results, the whole pathway of enymatic degradation of partially acetylated chitosan by a combination of chitosanase, exo-beta-D-glucosaminidase and beta-N-acetylhexosaminidase is proposed.