黄鳝孵卵泡的生化成分及其生理作用

通过对繁殖季节黄鳝为孵卵所吐的泡沫的特性和生化成分分析 ,孵卵泡的黏度为 2 72mPaS ,证明了该孵卵泡是糖蛋白 ,其中糖类含量为 0 15 6mg/mL ,蛋白质含量为 0 2 5 0mg/mL ,蛋白质 /糖类比值为 1 6 0。分离的泡沫蛋白经SDS PAGE电泳含 4种组分 ,分子量从小到大依次为 4 2 5kDa、5 8 6kDa、6 5 3kDa、98 2kDa。泡沫蛋白含 16种氨基酸 ,氨基酸总含量为 2 0 1 88mg/ 10 0mL。同时对孵卵泡的生理作用进行了分析和讨论     

柞蚕和柳蚕雌蛾粘液腺及内容物的研究对比分析

本实验测定了柳蚕卵表面的胶着物质的含量以及粘液腺的形状、大小,并对粘液腺的内容物进行了SDS一聚丙烯酰胺凝胶电泳分析。结果表明：柳蚕卵表面的胶着物质的含量为1．11mg／卵,与柞蚕（1．01mg／卵）相当。柞蚕、柳蚕雌蛾的粘液腺整体呈较细长的管状结构且几乎无枝状部分枝,柳蚕粘液腺的干状部长约为2．0cm,柞蚕为1．8cm,二者相近。柳蚕粘液腺的内容物经SDS-聚丙烯酰胺凝胶电泳分析出现了7条蛋白质谱带,分子量分别为114kD,92kD,78kD,53kD,50kD,23kD,12kD,与柞蚕存在差别。     

黄鳝性逆转与性腺蛋白关系的分析

实验采用聚丙烯酰胺梯度胶电泳方法，对２６２黄鳝的性腺蛋白进行了分析，结果表明雌性黄鳝随着性腺的成熟性腺蛋白组分有所增多，相反雄性黄鳝随着性原的成熟其性腺蛋白组分则有所减少；；雌鱼性腺Ⅱ－Ⅲ期为１０－１２条区带，雄鱼性腺Ⅲ－Ⅵ期为１３－１０条区带。兼性期性腺蛋白组分明显增加为１５－１９条区带，其增加的蛋白带为一组位于凝胶偏负极端、分子量相近的蛋白分子，性逆转时精巢的组建可能与这组蛋白的调节有关。性逆     

薏苡仁蛋白质组分研究

目的：对药食两用功能的薏苡仁蛋白质四类组分和氨基酸含量进行分析。方法：采用旋光法、索氏提取法、烘干法、马弗炉法分别进行淀粉、粗脂肪、水分和灰分的测定;采用顺序抽提法依次进行清蛋白、球蛋白、醇溶蛋白和谷蛋白的提取,用Brandford和凯式定氮法进行蛋白质含量分析;采用氨基酸分析仪进行氨基酸含量测定。结果：薏苡仁总蛋白含量为14．17％,其中清蛋白、球蛋白、醇溶蛋白和谷蛋白含量分别为0．20、0．88、6．34和5．30mg／100mg鲜重,分别占总蛋白质含量的1．43％、6．20％、44．74％和37．38％;薏苡仁粉经酸水解后共检测到15种氨基酸,除Trp外,人体必需氨基酸和半必需氨基酸均有检测到;各氨基酸含量也存在着差异,含量最高的为Glu（3．59mg／100mg）,含量最低的为Met（0．17mg／100mg）。结论：薏苡仁蛋白中醇溶蛋白和谷蛋白含量较丰富,为今后进一步开发薏苡仁功能食品提供了理论数据。     

低分子量核桃仁蛋白酶水解物抑制MCF-7细胞增殖

摘要：用木瓜蛋白酶制备核桃仁蛋白酶水解物,通过细胞增殖分析试验,研究其对人乳腺癌细胞（MCF-7）增殖的影响,结果显示：水解物具有明显的抑制细胞生长作用,IC50值为1.62mg/mL。用超滤方法将核桃仁蛋白酶水解物,分为10～5kDa、5～3kDa和＜3kDa3个组分,研究不同分子量范围的组分对MCF-7细胞增殖影响的结果表明,MW＜3kDa的低分子量组分具有较强的增殖抑制作用。对3个不同组分进行氨基酸含量分析,结果表明：具有较强抑制癌细胞生长作用的低分子量组分中,疏水性氨基酸及中性极性氨基酸含量较高,酸性极性氨基酸含量少于其他组分。     

乳杆菌表面粘附蛋白的提取、鉴定及粘附特异性的初步研究

以从健康牙鲆肠道中分离筛选的乳杆菌L15(Lactobacillussp.L15)和嗜酸乳杆菌ATCC4356为实验材料,应用5mol/L LiCl提取其表面蛋白,利用蛋白印迹法鉴定出在L15表面蛋白中分子量为61.8kDa和54.6kDa的蛋白质分别参与对牙鲆和鲤鱼粘液的粘附过程,为新发现的粘附蛋白种类,将其命名为MAPPpo1和MAPPcc。ATCC4356中分子量分别为43.0kDa和63.3kDa的两个表面蛋白参与对牙鲆粘液的粘附,而分子量为43.0kDa的蛋白参与对鲤鱼粘液的粘附。同时,蛋白质印迹法显示,L15和ATCC4356在牙鲆和鲤鱼肠粘液中均具有相同的粘附受体,在牙鲆肠粘液中是分子量为29.7kDa和30.3kDa的两种蛋白质,而在鲤鱼肠粘液中只有分子量为26.2kDa的蛋白作为受体参与L15和ATCC4356的粘附过程。结果显示,乳杆菌对肠粘液的粘附不但具有菌种的特异性,而且也有宿主的特异性。     

灰树花蛋白聚糖的提取、分离及氨基酸组成分析

目的:研究灰树花(Grifola frondosa)蛋白聚糖的提取与分离方法及氨基酸组成.方法:采用碱提法提取蛋白聚糖,QSepharose FF离子交换层析进行纯化,SDS - PAGE电泳分离蛋白聚糖及结合蛋白,高效液相色谱法鉴定蛋白聚糖的纯度及分子量,并测定18种氨基酸的含量.结果:分离出蛋白聚糖GFP Ⅰ、GFPⅡ和GFPⅢ,糖含量分别为:43.69％、40.88％、28.33％,蛋白含量分别为:40.42％、34.65％、51.19％.其中GFPⅢ为均一成分,纯度93.61％,重均相对分子量(Mr) 150kDa,GFPⅢ结合蛋白分子量约为33.0kDa,为单一谱带.氨基酸组成分析结果显示:GFPⅢ的氨基酸总和达到66.60g/100g,其中8种必需氨基酸总量为26.14g/100g,4种呈味氨基酸总量为25.43g/100g,Asp、Glu、Leu、Ala和Lys含量较高.结论:分离出的蛋白聚糖为结构均一成分,纯度较高,可用于质量研究和生物学研究.     

苦豆子游离氨基酸的成份测定

本文分析和鉴定了苦豆子中游离氨基酸的成份,测定出１６种游离氨基酸,总量为１６４．５２μｇ／１００ｍｇ,其中谷氨酸含量最高为４７．６８μｇ／１００ｍｇ,蛋氨酸含量最低为０．２０μｇ／１００ｍｇ,人体必须氨基酸有７种,占游离氨基酸总量的１７．３３％。     

大熊猫乳汁蛋白组成

测定了2只大熊猫（ailuropoda melanoleuca)乳汁中蛋白含量,乳糖含量,乳蛋白组成,并与成都麻羊（Capra hircus)初乳和中国荷斯坦牛（Bos taurus)乳进行了比较,大熊猫乳蛋白含量平均为41．52g/L,与中国荷斯坦牛乳接近;乳糖平均含量为15．41g/L,极显著低于牛乳和成都麻羊初乳,乳蛋白SDS－PAGE分析表明,大熊猫乳中酪蛋白（CN）含量明显低于羊乳和牛乳;乳中存在3条蛋白含量的区带,而在成都麻羊和中国荷斯坦牛乳电泳图谱的相应位置未见明显的区带,乳中上皮粘蛋白MUC1仅存在1条分子量约为196kDa的区带,未发现多态现象。     

四种鱼的血清、体表黏液SDS-PAGE分析

鱼类的血清和体表黏液在其适应复杂水体环境的生理生化反应中起着重要的作用。为了解鱼类血清和体表黏液的蛋白组分与含量的差异,采用SDS-聚丙烯酰胺凝胶电泳(SDS-PAGE)对体表黏液丰富的宽体沙鳅Sinibotia reevesae、中华沙鳅S.superciliars、长薄鳅Leptobotia elongata及南方鲇Silurus meridionalis四种鱼的血清与体表黏液的蛋白组分展开研究,共获得158条蛋白区带,其中血清67条,体表黏液122条,其分子量在10.92~194.48 k D之间。聚类分析显示宽体沙鳅血清蛋白与中华沙鳅的相似度最高(0.67),与南方鲇的相似度最低(0.40)。四种鱼的血清蛋白组分的差异体现了其在进化上的亲缘关系。而体表黏液蛋白组分中中华沙鳅与南方鲇的相似度最高(0.53),与长薄鳅的最低(0.47),未呈现出与血清类似的遗传分化规律。     

Cloning of habutobin cDNA and antithrombotic activity of recombinant protein

The habutobin cDNA was cloned from total RNA extracted from venom glands of Trimeresurus flavoviridis (the habu snake). The conceptual translation of 1539 bp of habutobin cDNA consists of 236 amino acids and its molecular weight is 25.7 kDa. Histidine (His)-tagged recombinant habutobin fusion protein, pET-r-habutobin and AcNPV-r-habutobin, was purified by bacterial system and baculoviral system, respectively. After refolding pET-r-habutobin, there were two protein bands at about 32 kDa and 65 kDa, indicating that habutobin might be produced as a monomer protein and processed to form two concatenated protein. Purified AcNPV-r-habutobin dose-dependently increased fibrin forming activity and inhibited collagen-induced aggregation of rabbit washed platelets. Thus, AcNPV-r-habutobin produced by baculoviral system is very useful for study on structure-function relationship, which is necessary for developing an antithrombotic drug from habutobin.     

水稻温敏失绿突变体的Rubisco活化酶活性、蛋白质与氨基酸组分的变化

在水稻温敏失绿突变性状表达过程中,对其Rutbsico含量、Rubsico活化酶活性,全叶蛋白及游离氨基酸组分变化进行测定。结果表明：突变体的Rubisco结构和含量与野生型一样,保持相对稳定;而其Rubisco活化酶活性则随一个分子量为56．2kD(PI=4．5)的特异蛋白质的存在与消失发生明显改变。当突变性状表达时,分子量为56.2kD(PI=4．5)的特异蛋白消失,其Rubisco活化酶活性下降;当叶片失绿区域复绿时,56.2kD(PI=4．5)特异蛋白出现,则Rubisco活化酶活性上升。这一密切地相关关系表明,突变体的Rubisco活化酶活性变化在光合作用过程中,除与自身结构和含量有关外,还与叶片中这一特异蛋白的存在密切相关,它可能是Rubisco活化酶活性的调节蛋白。这种调节具体表现在氨基酸代谢上,是对上游氨基酸的阻遏调控,从而使叶绿体的结构物质合成受阻,最终导致类囊体膜的退化。     

Chitinase from Bacillus thuringiensis subsp. pakistani

The chitinase gene (chiA71) from Bacillus thuringiensis subsp. pakistani consists of an open reading frame of 1,905 nucleotides encoding 635 amino acid residues with an estimated molecular mass of 71 kDa. Comparison of the deduced amino acid sequence of the mature enzyme to other microbial chitinases shows a putative catalytic domain and a region with conserved amino acids similar to that of the type III module of fibronectin and a chitin-binding domain. By activity detection of chitinase on SDS-PAGE after renaturation, the molecular mass of protein bands with chitinase activity were 66, 60, 47, and 32 kDa. The N-terminal amino acid sequence of each chitinase activity band was the same (Asp-Ser-Pro-Lys-Gln), suggesting that the 60-, 47-, and 32-kDa chitinases were derived from the 66-kDa chitinase by processing step(s) at the C-terminus. The enzyme was identified as an exochitinase, since it generated N-acetylglucosamine from early stage of colloidal chitin hydrolysis. The crude protein (2.3-18.4 mg/ml), containing chitinase at final activities of 8, 16, 32, and 64 mU/ml, was toxic to Aedes aegypti larvae and caused mortalities of 7.5, 15.0, 51.3, and 70.0% respectively, but the same amount of crude protein from a B. thuringiensis subsp. pakistani mutant lacking chitinase was not toxic.     

A simple method for determination of intramolecular amino acid sequence of unpurified protein. Application to human serum protein adsorbed by silica particles.

Silica particles adsorbed several kinds of human serum proteins, especially 23 kDa molecular weight protein. After SDS-PAGE of adsorbed serum proteins, gel pieces containing 23 kDa protein was cut out and set in slot of stacking gel in second SDS-PAGE following overlay of Staphylococcus aureus V8 protease. After electrophoresis, gel was subjected to electroblotting onto polyvinylidene difluoride membrane. Both bands of dye-stained 23 kDa and the peptide were cut out from membrane and analyzed for amino acid sequence. Obtained sequences agreed well with amino terminal and intramolecular sequences of human HDL-apolipoprotein, A-I.     

Partial purification of the aminopeptidase from the midgut of the human body louse, Pediculus humanus humanus

The midgut of the human body louse Pediculus humanus humanus contains a thermally stable leucine aminopeptidase, which was detected by agarose gel electrophoresis using l ‐amino oxidase. Midgut extracts were homogenized in saline or in 1% Triton X‐100 and the aminopeptidase was purified by Superose 6 gel filtration chromatography. A peak with enzyme activity that was extracted with or without Triton X‐100 was eluted at a molecular weight 67–69 kDa. Non‐denaturing polyacrylamide gel electrophoresis resolved one band of molecular weight of 69 kDa for samples that were extracted in a saline buffer. Two closely linked bands of molecular weight 67 kDa and 69 kDa were observed in samples that were extracted in 1% Triton X‐100.     

Chemical characterization of the serum very low density and high density lipoproteins from bullfrog, Rana catesbeiana.

The chemical properties of very low density and high density lipoproteins of adult bullfrog serum were determined. This serum contained extremely low levels of both very low density lipoprotein (10-30 mg/100 ml) and high density lipoprotein (5-10 mg/100 ml). The constituents of very low density lipoprotein, on a weight percentage basis, were found to be 48.1% triglyceride, 17.3% cholesterol ester, 8.8% cholesterol, 11.6% phospholipid, and 12% protein. These constituents were also present in high density lipoprotein with weight percentage values of 3.7%, 19.3%, 11.9%, 25.2%, and 36.8%, respectively. The fatty acid compositions of the triglycerides, cholesterol esters, and phosphatidylcholine were quite similar in the very low density lipoprotein and high density lipoprotein. However, shingomyelin fatty acid composition was appreciably different in the two lipoproteins. Disc gel electrophoresis in sodium dodecyl sulfate-polyacrylamide gels produced patterns with one major (approximate molecular weight, 7,000) and several minor bands for the apoprotein of very low density lipoprotein and one major (approximate molecular weight, 28,000) and several minor bands for that of high density lipoprotein.     

Comparative study of enterostatin sequence in five rat strains and enterostatin binding proteins in rat and chicken serum

Enterostatin, a pentapeptide derived from the precursor protein procolipase has been shown to inhibit dietary fat intake and to reduce body fat after chronic administration in rats. We repeat that the enterostatin amino acid sequence from the genomic DNA of 5 different rat strains is APGPR. 125I-APGPR bound to three proteins (300, 205 and 60 kDa) in rat serum and one 60 kDa protein in chicken serum. These serum binding proteins were also eluted by APGPR affinity chromatography. Western blot analysis of serum protein identified enterostatin-like immunoreactivity associated with the same molecular weight bands. Our results demonstrate the enterostatin sequence in rat is APGPR and suggest the presence of enterostatin binding proteins in rat and chicken serum.     

Paramphistomum cervi: antigenic profile of adults as recognized by infected cattle sera

An antigenic profile of adult Paramphistomum cervi was revealed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting using sera from cattle naturally infected with P. cervi, Fasciola gigantica and strongylids. SDS-PAGE of whole worm extracts exhibited 26 distinct protein bands. Immunoblotting analysis of these proteins showed five major antigenic bands which were recognized by serum of individual cattle naturally infected with P. cervi. These antigenic proteins had molecular weights ranging from 23 to 116kDa. One antigenic protein with a molecular weight of 52kDa exhibited a consistent reaction with sera from all infected cattle. It's diagnostic sensitivity, specificity and accuracy using this test were 100%, 98% and 98.9%, respectively. The positive and negative predictive values were 97.6% and 100%, respectively. This finding suggests that the 52kDa protein may be a diagnostic antigen for paramphistomosis.     

Amino acid sequences of proteins from Leptospira serovar pomona

This report describes a partial amino acid sequences from three putative outer envelope proteins from Leptospira serovar pomona. In order to obtain internal fragments for protein sequencing, enzymatic and chemical digestion was performed. The enzyme clostripain was used to digest the proteins 32 and 45 kDa. In situ digestion of 40 kDa molecular weight protein was accomplished using cyanogen bromide. The 32 kDa protein generated two fragments, one of 21 kDa and another of 10 kDa that yielded five residues. A fragment of 24 kDa that yielded nineteen residues of amino acids was obtained from 45 kDa protein. A fragment with a molecular weight of 20 kDa, yielding a twenty amino acids sequence from the 40 kDa protein.     

Suppression of phaseolin and lectin in seeds of common bean, Phaseolus vulgaris L.: increased accumulation of 54 kDa polypeptides is not associated with higher seed methionine concentrations

Suppression of phaseolin and lectin accumulation in common bean resulted in higher concentrations of bean seed polypeptides with apparent molecular weights of 54 kDa and from 70 to 84 kDa on SDS-polyacrylamide gel electrophoresis. Polypeptides of 54 and 56 kDa segregated as products of different alleles. Genes for the 54/56 kDa bands and phaseolin were estimated to be 26.2±3.7 map units apart. The 54 kDa band phenotype manifested by SDS-PAGE consisted of from one to three polypeptides of 54 kDa MW on 2D gels, and the 56 kDa phenotype consisted of one polypeptide of 56 kDa plus two minor polypeptides of 54-54.5 kDa molecular weight. The pK_I of these polypeptides was approximately 5.25. The methionine content of the 54 kDa polypeptides of the cultivar Great Northern Star was 1.6±0.1 g/100 g protein, which was not statistically different from the value (1.5±0.1%) obtained for phaseolin isolated by the same procedure. F₂ seeds deficient for phaseolin and lectin contained as much total N per g as wild-type seeds and were not shrunken, but contained 50% more free amino acids. F₂ seeds from two of the three populations contained from 8 to 13% less methionine per mg total N.