枸杞果实铁型超氧物歧化酶的纯化及性质

枸杞果实Ｆｅ－ＳＯＤ粗提液经硫酶铵盐析、离子交换柱层析及凝胶过滤,纯化到电泳单班点均一程度。纯化的Ｆｅ－ＳＯＤ分子量为４４．６ｋＤ,亚基分子量为２２．０ｋＤ。金属元素分析表明,每分子酶含１个Ｆｅ原子。该酶在紫外区最大吸收值为２７８ｎｍ。Ｈ２Ｏ２明显抑制该酶活性,ＫＣＮ对酶活性无影响。该酶氨基酸组成与高等植物和蓝绿藻的Ｆｅ－ＳＯＤ相似,但它具有较高甘氨酸,酸性氨基酸与碱性氨基酸比值高于等植物而与低等     

菠菜铁型超氧化物歧化酶的纯化及性质

用聚丙烯胺梯度凝胶电泳法检测出菠菜ＳＯＤ同工酶谱带中含３条Ｆｅ－ＳＯＤ活性带,菠菜叶Ｆｅ－ＳＯＤ粗提取液经硫酸铵分部沉淀,ＤＥＡＥ－纤维素－Ａ５２和ＳｅｐｈａｄｅｘＧ－１００柱层析,纯化出单一的Ｆｅ－ＳＯＤ活性带,纯化酶的分子量为４２．６ｋＤ,亚基分子量为２１ｋＤ。对金属元素的分析表明,该酶每分子含２．６个Ｆｅ原子,该酶紫外区最大吸收峰为２７８ｎｍ,等电点为４．６,氨基酸组成和其它来源的Ｆｅ－ＳＯ     

贻贝（Perna viridis）超氧化物歧化酶的纯化及部分性质研究

采用５５－６０℃热处理,硫酸铵分级深沉和ＤＥＡＥ－ＳｅｐｈａｒｏｓｅＦＦ柱层析将贻贝Ｃｕ,Ｚｎ－ＳＯＤ纯化到均一程度。每１００ｇ鲜贻贝肉可得到ＳＯＤ制品,总活力３６８９ｕ,比活力７８２ｕ／ｍｇ,回收率为２１％。测得该酶分子量为３２ｋＤ,亚基分子量约为１６．４ｋＤ,最大紫外吸收波长为２６８ｎｍ,,贻贝Ｃｕ,Ｚｎ－ＳＯＤ具有一定的耐热性,较强的抗酸、抗碱及抗脲性。     

甲基单胞菌Methylomonas sp.GYJ3中甲烷单加氧酶还原酶组分的纯化和性质

Ｍｅｔｙｌｏｍｏｎａｓｓｐ．ＧＹＪ３菌的甲烷单加氧酶（ＭＭＯ）粗酶提取液经ＤＥＡＥ－ＳｅｐｈａｒｏｓｅＣＬ－６Ｂ阴离子交换层析、ＳｅｐｈａｄｅｘＧ－１００凝胶过滤层析和ＤＥＡＥ－ＴＳＫｇｅｌＨＰＬＣ分离纯化出ＭＭＯ还原酶组分．经ＨＰＬＣ分析,纯度大于９５％,纯化倍数为４．４,加入至ＭＭＯ羟基化酶和调节蛋白Ｂ的体系中表现比活为２２８ｎｍｏｌ环氧丙烷每分钟毫克蛋白．ＳＤＳ－ＰＡＧＥ电泳表明还原酶由一种亚基组成,分子量４２ｋＤ．ＩＣＰ－ＡＥＳ测定还原酶的Ｆｅ含量为１．８３ｍｏｌＦｅ每ｍｏｌ蛋白．ＵＶ－Ｖｉｓ光谱表明还原酶除２８０ｎｍ蛋白质特征峰外在４６０ｎｍ有最大吸收峰,且Ａ２８０ｎｍ／Ａ４６０ｎｍ为２．５０,与其它黄素一铁硫蛋白相似,推测还原酶可能含一个ＦＡＤ辅基和Ｆｅ２Ｓ２中心．在厌氧条件下,还原酶能够和ＮＡＤＨ作用,ＵＶ－Ｖｉｓ光谱分析表明还原酶４６０ｎｍ处特征吸收峰消失,说明在ＭＭＯ催化过程中还原酶接受ＮＡＤＨ的电子．ＤＥＡＥ－ＳｅｐｈａｒｏｓｅＣＬ－６Ｂ阴离子交换层析分离出调节蛋白Ｂ,部分纯化的调节蛋白Ｂ的分子量大约在２０ｋＤ,它能够提高ＭＭＯ比活性４０倍,ＭＭＯ还原酶和调节蛋白Ｂ单独存在时不具有ＭＭＯ     

中温碱性脂肪酶的研究：Ⅲ.扩展青霉PF868变株碱性脂肪酶的纯化及其…

扩展青霉ＰＦ８６８变株发酵液经硫酸铵盐析和Ｓｅｐｈａｄｅｘ－Ｇ－２００及Ｓｅｐｈａｒｏｓｅ４Ｂ柱层析纯化,获得纯化倍数为３２．４的酶粉。该酶分子量为２３４４２Ｄａｌ,酶学特性表明：该酶的最适作用温度为３２℃,５０℃保温３０ｍｉｎ仍保留５０％酶活性,最适ｐＨ为９．０,作用ｐＨ稳定范围在７．０－１０．０之间,Ｃａ＾２＋和Ｍｇ＾２＋对酶有激活作用,Ｆｅ＾２＋,Ｃｕ＾２＋和Ｍｎ＾２＋酶活力有抑制作用。     

蜡质芽孢杆菌超氧化物歧化酶的理化性质研究

本文对从蜡质芽孢杆菌发酵菌体中纯化的Ｆｅ－ＳＯＤ进行了理化性质研究,测定结果表明：在２７℃,ｐＨ６８,光照强度为４０００Ｌｕｘ条件下,光照２０分钟为酶活性测定的最佳条件;经ＳＤＳ－聚丙烯酰胺凝胶电泳分析得其亚基分子量为１７,７８３道尔顿;等电聚焦电泳表明：Ｆｅ－ＳＯＤ的等电点（ＰＩ）大约为６５左右;经ＤＮＳ法分析Ｎ－末端氨基酸为谷氨酸（Ｇｌｕ）;其氨基酸的组成中酸性氨基酸的含量大于碱性氨基酸的含量,表明此酶为酸性蛋白。     

甲基单胞菌Methylomonas sp.GYJ3中甲烷单加氧酶羟基化酶组分…

从Ｍｅｔｈ ｙｌｏｍｏｎａｓ ｓｐ．ＧＹＪ３菌株中经ＤＮＥＡＥ－ＳｅｐｈａｒｏｓｅＣｌ－６Ｂ阴离子交换层析和ＳｅｐｈａｃｒｙｌＳ３００凝胶层析分离出纯化出甲烷加氧酶羟基酶组分,经ＨＰＬＣ分析,纯度大于９０％,分子量为２４０ｋＤ,纯化们数为３．９,比活为２２５ｎｍｏｌ环氧丙烷每分钟毫克蛋白,ＳＤＳ－ＰＡＧＥ表明,羟基化酶由三个亚基组成,亚基分子量为５６、４３、２７ｋＤ．ＩＣＰＡＥＳ测定羟基化酶的Ｆｅ     

林生山黧豆谷氨酸脱羧酶的分离纯化及部分性质的研究

以林生山黧豆为材料,利用硫酸铵分段盐析,丙酮沉淀,ＤＥＡＥ－ＳｅｐｈａｒｏｓｅＦＦ离子交换柱层析,ＳｅｐｈａｃｒｙｌＳ３００凝胶过滤柱层析及ＦＰＬ－ＭｏｎｏＱ柱层析技术,以聚酰胺薄膜层析荧光定量法为酶活力检测手段,分离纯化了谷氨酰羧酶,达到电泳银染纯,纯化后的林生山黧豆谷氨酸脱羧酶活力达３７５．０９Ｕ．ｍｇ＾－１,纯化保数３８．２倍,经ＳＤＳ－ＰＡＧＥ测定,其亚基分子量为７０ｋＤ,经工ＰＡＧＥ确定     

韭菜线粒体锰超氧化物歧化酶纯化及性质研究

经硫酸铵沉淀、ＤＥＡＥ－Ｓｅｐｈａｃｅｌ层析和Ｓｅｐｈａｄｅｘ Ｇ－２００凝胶过滤,将韭菜线粒体ＳＯＤ纯化到均一程度。从６０００ｇ韭菜叶片线粒体中纯化得到２．５ｍｇ酶,酶比活力达１２００Ｕ／ｍｇ蛋白。该酶对ＫＣＮ和Ｈ２Ｏ２都不敏感,热稳定性弱 外光区吸收峰在２８０ｎｍ,凝胶过滤法测得其分子量为８２００Ｄ,ＳＯＳ－ＰＡＧＥ法测定其亚基分子量的２２０００Ｄ,ＤＮＳ法测得其Ｎ－末端氨基酸为缬氨酸。上述结     

何首乌叶铜锌超氧物歧化酶纯化及性质

何首乌（ＰｏｌｙｇｏｎｕｍｍｕｌｔｉｆｌｏｒｕｍＴｈｕｎｂ．）叶Ｃｕ·ＺｎＳＯＤ经硫酸铵盐析、离子交换柱层析及葡聚糖凝胶过滤等步骤,被分离成两组ＳＯＤ同工酶（ＳＯＤ１,ＳＯＤ２）,它们被纯化到均一程度。ＳＯＤ１分子量为３２．４ｋＤ,亚基分子量为１６．２ｋＤ,最适ｐＨ值为５０,在６０℃和６５℃时的半衰期分别为１４ｍｉｎ和８ｍｉｎ;ＳＯＤ２分子量为３０５ｋＤ,亚基分子量为１５９ｋＤ,最适ｐＨ值为６０,在６０℃和６５℃时半衰期分别为３２ｍｉｎ和１６ｍｉｎ,它由２７４个氨基酸残基组成,不含Ｃｙｓ、Ｔｙｒ和Ｔｒｙ。ＳＯＤ１和ＳＯＤ２每ｍｏｌ酶都含有２ｍｏｌＣｕ和２ｍｏｌＺｎ,它们在紫外区最大吸收波长均为２７５ｎｍ。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

Synthesis and antimicrobial studies of hydrazone derivatives of 4-[3-(2,4-difluorophenyl)-4-formyl-1H-pyrazol-1-yl]benzoic acid and 4-[3-(3,4-difluorophenyl)-4-formyl-1H-pyrazol-1-yl]benzoic acid

Microbial resistance to antibiotics is an unresolved global concern, which needs urgent and coordinated action. One of the guidelines of the Centers for Disease Control and Preventions (CDC) to combat antibiotic resistance is the development of new antibiotics to treat drug-resistant bacteria. In our effort to find new antibiotics, we report the synthesis and antimicrobial studies of 30 new pyrazole derivatives. These novel molecules have been synthesized by using readily available starting materials and benign reaction conditions. Some of these molecules have shown activity with MIC values as low as 0.78?µg/mL against four bacterial strains; Staphylococcus aureus, methicillin-resistant S. aureus, Bacillus subtilis, and Acinetobacter baumannii. Furthermore, active molecules are non-toxic to mammalian cell line.

     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Novel compounds with potent CDK9 inhibitory activity for the treatment of myeloma

Cyclin-dependent kinases (CDKs) and Polo-like kinases (PLKs) play key role in the regulation of the cell cycle. The aim of our study was originally the further development of our recently discovered polo-like kinase 1 (PLK1) inhibitors. A series of new 2,4-disubstituted pyrimidine derivatives were synthesized around the original hit, but their PLK1 inhibitory activity was very poor. However the novel compounds showed nanomolar CDK9 inhibitory activity and very good antiproliferative effect on multiple myeloma cell lines (RPMI-8226).