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1.
千针万线草环肽A的结构修正   总被引:6,自引:1,他引:5  
从云南民间药物千针万线草(Stellaria yunnanensis)的根中分离到一新环肽stellarinA。前报主要利用快速原子轰击质谱确定其结构为cyclo(Gly-Pro-Phe-Tyr-Gly-Gly-Pro)。最近利用最新二维核磁结合快速原子轰击质谱及酶降解重新考察了其结构,修正为cyclo(Gly-Pro-Phe-Pro-Gly-Tyr-Gly)。  相似文献   

2.
王不留行环肽研究   总被引:9,自引:2,他引:7  
从中药王不留行(Vacariasegetalis)种子中分离并鉴定了4个环肽化合物,分别命名为王不留行环肽A,B,C,D(vaccarinsA,B,C,D),其中王不留行环肽A为新环肽化合物。其结构通过光谱和化学方法分别确定为:vaccarinA——cyclo-(Trp-Ala1-Gly-Val-Ala2),vaccarinB———cyclo-(Pro-Gly-Leu-Ser-Phe1-Ala-Phe2),vaccarinC———cyclo-(Pro1-Gly-Tyr-Val-Pro2-Leu-Trp),vacarinD———cyclo-(Pro-Val1-Trp-Ala-Gly-Val2).  相似文献   

3.
我们针对肝细胞特异的ASGP(去唾液酸糖蛋白)受体,构建了一种具有肝细胞特异导向性的基因转移载体系统,该载体包括两种共价结合的功能成分:一种为ASGP,作为配体,与肝细胞表面特异的ASGP受体结合;另一种为多聚左旋赖氨酸(poly-L-lysine),与DNA以强静电作用相结合。小鼠尾静脉注射32P-DNA-poly-L-lysine-ASOR(去唾液酸al酸性糖蛋白)或等量的32P-DNA、ASOR、poly-DL-lysine单体混合物,20小时后,小鼠肝、脾、肾各组织的放射性计数结果表明该载体系统具有较强的肝组织特异性。  相似文献   

4.
猪脑组织提取液经SephadexG-50分子筛层析,S-SepharoseFastFlow阳离子交换柱层析及两次HPLC分离得到一分子量为12000,等电点PI7.1的多肽,并测定了其氨基酸组成和N末端部分序列:N-Phe-Lys-Gly-Phe-Pro-Asp-Asp/(Lys)-Lys/(Asp)-Asp-Tyr,给昆明小鼠脑室注射或尾静脉注射肽均能抑制吗啡引起的镇痛作用,其作用随着注射剂量的  相似文献   

5.
曾在一个儿童患者体内,发现一个新的乙型肝炎病毒(HBV)变异株,其HBsAg主蛋白aa126发生Ile(ATT)到Ser(AGT)的取代。已知adr/ayr亚型HBsAg126位为Ile,而adw/ayw亚型HBsAg126位为Thr,表明HBsAg126Ser是一个新的变异株。用计算机做结构分析的结果表明,突变体HBsAg126Ser主蛋白aa120-aa130区段的二级结构与野生型adrHBVHBsAg126Ile相比发生明显的改变。这种构象的变化可能会影响a抗原决定簇(a124-aa147)的抗原性。为了证实这一点,构建了突变S基因表达质粒,在SV40早期启动子的控制下进行抗原表达。利用HBsAg9肽(Thr-Ile126-Pro-Ala-Gln-Gly-Thr-Ser-Met)抗i单克隆抗体和9肽(Thr-Thr126-Pro-Ala-Gln-Gly-Thr-Ser-Met)抗t单克隆抗体进行放射免疫测定,结果表明,这种Ser126突变蛋白对抗i单克隆抗体的反应性比野生蛋白减弱,对抗t单克隆抗体的反应性则与HBsAg126Thr接近。但用三种抗-a单克隆抗体的检测结果揭示,突变蛋白HBsAg126  相似文献   

6.
从织锦芋螺中克隆α芋螺毒素序列   总被引:13,自引:0,他引:13  
为了从我国南海产织锦芋螺(Conustextile)中分离新的毒素序列并研究其应用价值,进行了织锦芋螺毒素基因的分离工作.从织锦芋螺毒管中提取mRNA,以A族芋螺毒素的信号肽编码部分和3′端非翻译部分的保守序列为引物,通过RT-PCR扩增和序列分析方法获得新的芋螺毒素序列.结果得到两种不同的α芋螺毒素序列,两者都属于α4/7亚型芋螺毒素,预测其成熟肽序列分别为Pro-Glu-Cys-Cys-Ser-Asp-Pro-Arg-Cys-Asn-Ser-Ser-His-Pro-Glu-Leu-Cys-Gly(C端Gly可能被酰胺化)和Pro-Glu-Cys-Cys-Ser-His-Pro-Ala-Cys-Asn-Val-Asp-His-Pro-Glu-Ile-Cys-Arg.采用传统的生化分离手段尚未从织锦芋螺中获得过α芋螺毒素序列,这两种α芋螺毒素作用的种属特异性、受体类型特异性和在小细胞肺癌的诊断和治疗中的应用价值有待进一步研究  相似文献   

7.
通过培养的人主动脉平滑肌细胞(hASMC)及脐静脉内皮细胞(hUVEC),应用3H-TdR参入、Northernblot分析、逆转录多聚酶链反应(RT-PCR)、放射免疫分析(RIA)、和紫外比色法等技术观察了人主动脉中硫酸乙酰肝素蛋白聚糖(HSPG)对hASMC和hUVECDNA合成的作用及对血小板源生长因子(PDGF)、PDGF受体、转化生长因子β(TGF-β)、内皮素-1(ET-1)或碱性成纤维细胞生长因子(bFGF)基因表达和肾素-血管紧张系统(RAS)的影响,结果显示,HSPG明显抑制培养的hASMC基础的DNA合成(cpm值为:10385±3263vs,25541±6421,P<0.01)及外源性PDGF诱导的DNA合成(cpm值为:9878±1947vs.13481±44l0,P<0.05);抑制PDGFA链、TGF-Bp和ET-1mRNA表达,提高PDGFa和β受体mRNA的表达;显著降低hASMC培养液中血管紧张素Ⅱ(AngⅡ)的浓度和血管紧张素转换酶(ACE)的活性,推测HSPG抑制PDGFA链、TGF-β及ET-1mRNA表达,降低ACE活性及AngⅡ浓度是其抑制hASMC增殖的重要机  相似文献   

8.
少棘巨蜈蚣(ScolopendrasubspinipesmutilansL.Koch)经95%乙醇脱脂后,再经4℃水冷渗,水提液低温旋转浓缩,冻干,得到的冻干粉先后经过SephadexG-25柱,等电聚焦制备电泳,再经SephadexG-150柱,SephadexG-100柱,最后经HPLC制备得到一个纯的碱性蛋白,命名为SSmp-d.该蛋白经HPLC、超薄等电聚焦电泳检验是均一的.采用HPLC和Protein-PakTM125柱测定其分子量为24.64kD.IEF-HPCE显示其等电点为9.27.氨基酸分析表明SSmp-d含较多的Arg、Lys等碱性氨基酸,另外还含有较多的Ala、Leu.使用蛋白质自动序列分析仪测定了SSmp-dN端的11个氨基酸,序列为NH3+-Asp-Val-Asn-Phe-Arg-Leu-Ser-Gly-Ala-Asp-Pro.  相似文献   

9.
山茶属—新组──柱蕊茶组闵天禄(中国科学院昆明植物研究所,昆明650204)SECT.CYLINDRICA,ONENEWSECTIONOFGENUSCAMELLIA(THEACEAE)¥MINGTien-Lu(KunmingInstituteofBo...  相似文献   

10.
识别未衍生化的13—羟化GAs及其葡萄糖苷的单克隆抗体   总被引:21,自引:0,他引:21  
抗GA3 及其葡萄糖苷的MAB10单克隆抗体源于以GA3 中的3 位羟基(3-OH)为偶联位点,人血清白蛋白(HSA)为载体合成的GA3-3-HSA 免疫原. 该抗体对13-羟化GAs(13-OHGAs、GA1、GA3、GA5 等)和GA3 葡萄糖苷具有高亲和力. 7 位羧基的甲酯化可显著降低MAB10 对13-OH GAs的亲和力,而3-OH 的糖苷化却未降低其亲和力. 用该抗体建立的两种分别用于GA3 及其葡萄糖苷测定的酶联免疫吸附法(ELISA),其检测线性范围均为0.2~20 pm ol. 借助这两种ELISAs,研究了羊蹄(Rum ex japonicus)叶片中GA3 及其类似GAs和葡萄糖苷的动态变化.结果表明,叶片衰老与游离态GAs的糖苷化有关;而6-BA 延缓衰老则可能与其减缓GAs的糖苷化有关  相似文献   

11.
Isolation and sequence analysis of human bombesin-like peptides   总被引:4,自引:0,他引:4  
The decapeptide form of human gastrin releasing peptide was isolated from acid extracts of liver tissue containing a metastatic human bronchial carcinoid tumor. A larger form also was isolated and partially characterized. During gel permeation chromatography the major immunoreactive peak eluted in the same region as synthetic gastrin releasing decapeptide while a second minor immunoreactive peak eluted near gastrin releasing peptide. Bombesin-like immunoreactivity (BLI) was purified by successive applications to reverse phase high pressure liquid chromatography (HPLC) columns. After four successive HPLC purifications a single peak of bombesin-like immunoreactivity was detected. Amino acid analysis, microsequence analysis and coelution with synthetic peptide indicated that the predominant form present in metastatic tumor tissue was identical to the decapeptide form of canine gastrin-releasing peptide. The less abundant form was purified by cation exchange chromatography followed by reverse phase high pressure liquid chromatography. Partial microsequence analysis of this peptide, through the first 11 residues, was Val-Pro-Leu-Pro-Ala-Gly-Gly-Gly-Thr-Val-Leu. This sequence differed from that of hog heptacosapeptide gastrin releasing peptide at positions 1,3,4 and 5 and from the canine peptide as positions 1,3,5, and 7.  相似文献   

12.
The preparation of two highly purified lipolytically active hog pituitary peptides, called P-LF II C and P-LF II D is described. The two peptides are free of other pituitary hormone activities. In isolated rat and porcine adipose tissue, both fractions are lipolytically much more active than every other lipolytic active pituitary peptide described to date. By fraction P-LF II D, the first pituitary peptide was isolated which has lipolytic activity in isolated rat adipose tissue than corticotropin, the lipolytically most active pituitary hormone known so far. On isolated porcine adipose tissue, fraction P-LF II D as well as P-LF II C showed without doubt higher activity than corticotropin.  相似文献   

13.
Highly purified hog liver flavin-containing monooxygenase was sequentially denatured, reduced, carboxymethylated, and digested with endoproteinase Glu-C. The purified peptides were subjected to mass spectrometric analysis and the amino acid sequence of selected fragments was determined by tandem mass spectrometry. The amino acid sequence of the first 12 residues of the N-terminus was: Ac-Ala-Lys-Arg-Val-Ala-Ile-Val-Gly-Ala-Gly-Val-Ser-Gly. The amino acid sequence determined for another peptide was: Lys-Ser-Val-Leu-Val-Val-Gly-Met-Gly-Asn-Ser-Gly-Thr-Asp-Ile-Ala-Val-Glu. The results provide direct evidence for the structure of the N-terminal modification of the protein and for the existence of the FAD and NADP binding domains of Gly-X-Gly-X-X-Gly.  相似文献   

14.
1. By means of an enzyme immunoassay, the contents of D-amino acid oxidase (DAO) were determined in kidney, liver, cerebellum and lung of hog, but the oxidase was not detectable in heart or cerebrum. 2. The oxidases in kidney, liver and cerebellum of hog were indistinguishable as regards immunoreactivity toward anti-hog kidney DAO antibody, specific activity and molecular weight. 3. The oxidases in rat and dog kidneys immunochemically cross-reacted with anti-hog DAO antibody. 4. The overall structure of the hog oxidase was more similar to that of the dog enzyme than that of the rat, while the structure around the catalytic site of the hog oxidase was more similar to that of the rat oxidase than that of the dog enzyme. 5. On immunoblot analysis, two forms of the oxidase were detected in extracts of hog, rat and dog kidneys.  相似文献   

15.
In the absence of detectable cytologic changes in hog cholera virus-infected tissue culture cells, hog cholera viral antigen was readily detected by immunofluorescence. The ability to detect hog cholera viral antigen by this method allowed for determination of infectivity titers and also for titration of homologous antibody. Immunofluorescence made possible the identification, in tissue culture, of hog cholera virus from blood, serum, and spleen extracts of experimentally infected swine. Further applications of this method and its limitations are being investigated.  相似文献   

16.
Human granulocyte elastase (EC 3.4.21.11) differs from hog pancreatic elastase in its specificity for synthetic substrates. Although hydrolyzing peptide bonds adjacent to the carboxyl group of alanine, the granulocyte enzyme prefers valine at the cleaved bond, in contrast to the pancreatic enzyme which prefers alanine. Peptide bonds involving the carboxyl group of isoleucine can be hydrolyzed by the granulocyte enzyme but are not hydrolyzed to any significant extent extent by pancreatic elastase. This difference in specificty could explain the lower sensitivity of the granulocyte enzyme to inhibitors containing alanine analogs, such as the peptide chloromethyl ketones and elastatinal. The human granulocyte chymotrypsin-like enzyme differs from pancreatic chymotrypsin by being able to cleave substrates containing leucine in addition to those containing the aromatic amino acids.  相似文献   

17.
Leucine aminopeptidase (LAP) was purified from hog lenses by application of the Himmelhoch procedure for isolation of hog kidney LAP [S. R. Himmelhoch (1970) in Methods in Enzymology (Perlmann, G. E., and Lorand, L., eds.), Vol. 19, pp. 508-513, Academic Press, New York.] This involved treating crude hog lens homogenates with hexadecyltrimethylammonium bromide, DEAE-cellulose adsorption and elution, ammonium sulfate fractionation (53-84% of saturation), and gel filtration on a Bio-Gel A-1.5m column. Purifications ranging from 2080- to 4700-fold with activity yields from 28 to 100% were achieved. The hog lens LAP appeared homogeneous by native and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (PAGE). Bio-Gel chromatography of the native enzyme and SDS-PAGE of dimethylsuberimidate-crosslinked LAP indicated a molecular weight of 326,000. SDS-PAGE of untreated LAP showed a subunit weight of 54,000, consistent with a hexameric enzyme structure. By immunodiffusion, LAP from hog lens and kidney were identical while hog lens and beef lens enzymes demonstrated only partial identity. Electrophoresis of the native enzymes showed a slightly lower mobility for the hog lens LAP than for beef LAP at pH 8.7.  相似文献   

18.
R Dimaline  G J Dockray 《Life sciences》1979,25(22):1893-1899
Molecular forms of vasoactive intestinal polypeptide (VIP) have been examined in the gut and brain of dog, rat and hog. Fractionation of acid extracts on CM-Sephadex revealed three components cross-reacting in a radioimmunoassay using an amino-terminal specific antiserum. One of the components was compatible with standard porcine octacosapeptide VIP, the other two eluted earlier and are so likely to be less positively charged peptides. However, after gel filtration on Sephadex G50, the same peaks of activity eluted in a similar position to porcine VIP indicating similar molecular size. There were marked species differences in the distribution of the different molecular forms. For example, in both muscle and mucosal layers of the rat intestine 50–90% of total immunoreactive VIP was attributable to the molecular variants, while in hog colon the variants were found predominantly in the mucosa and accounted for about 50% of total immunoreactivity. In contrast a form of VIP compatible with the authentic peptide accounted for over 75% of activity in the brain of all three species. The biological activity of the VIP variants is not known but clearly caution needs to be exercised in interpreting the physiological significance of studies on the action, release and metabolism of VIP.  相似文献   

19.
应用Sysmex F-820血球计数仪和Olympus AU400全自动生化分析仪,对成都动物园圈养的16只豚鹿的46个血液样本进行血液细胞及血液化学43项指标检测,并对成体、亚成体及幼体进行统计分析,建立了一个参考指标.这对豚鹿的疾病诊断和繁育研究具有重要的意义.  相似文献   

20.
A small peak in the amino acid analysis of hog thyroglobulin was observed in the region reported for lysinoalanine and galactosamine. Since galactosamine had been previously reported absent in hog thyroglobulin, the possibility that this peak was lysinoalanine, a potential product of the coupling of two iodotyrosines, was investigated. Tests, however, showed that the material was galactosamine and that hog thyroglobulin contains no significant amount of lysinoalanine. Approximately 5 moles of galactosamine were found per mole of thyroglobulin.  相似文献   

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