猪血红蛋白的酶解及氨基酸含量的研究

猪血是一种营养价值高而价格低廉的蛋白质资源.猪血中含有丰富的蛋白质,其中血红蛋白占主要部分.因此,对血红蛋白及其水解产物的研究受到了国内外众多学者的关注.为选出适合于水解猪血红蛋白的蛋白酶,笔者采用碱性蛋白酶、木瓜蛋白酶、中性蛋白酶对猪血进行单酶和复合酶水解试验,确定碱性蛋白酶为水解猪血的适用酶.通过质谱仪测定,碱性蛋白酶酶解产物分子量集中在800～2400道尔顿,而800～1260道尔顿区间占主要部分;经全自动氨基酸分析仪测出其产物含有17种氨基酸,其中含8种必需氨基酸,必需氨基酸占总氨基酸量的50.93%,说明碱性蛋白酶酶解产物是制作食品和饲料添加剂的理想资源.     

鲜胰多酶水解猪血及血粉制备食用蛋白

<正> 为了开辟猪血的利用途径,考虑到猪血低脂、低糖、高蛋白的特点和猪血蛋白中具备八种人体必需氨基酸,其中L-赖氨酸高达14％以上,是补充人体蛋白源不足的理想营养品。尤其低脂、低糖、富含L-赖氨酸特点更有利老年人、妇女和正在生长发育的儿童的需要,对高血脂患者又是极好的蛋白质来源。猪血中还含维生素,酶、盐、低分子氮化物、葡萄糖,又含人体不可缺少的微     

从猪血水解液中提取酸性、碱性氨基酸和亮氨酸

<正> 猪血中含有丰富的蛋白质。试验结果表明,猪血由除去大量水份外,约含20％～25％的干物质。这种干物质主要成份为蛋白质。应用猪血粉为蛋白质原料水解提取氨基酸的方法国内已见报道。我厂自1978年起开始研究直接利用猪血作为蛋白质原料水解提取酸性、碱性氨基酸和亮氨酸。经过努力,我们采用较高的流速,用732阳离子交换树脂柱将水解液中氨基酸粗略分离分组,然后利用一些氨基酸的     

Population status and conservation of an extremely small population species Euryodendron excelsum

猪血木(Euryodendron excelsum)是特产于中国的山茶科极危种, 但目前对导致猪血木种群结构改变的原因缺少相关的调查及研究, 保护策略不完善。该研究依据野外调查方法、编制标准生命表、存活曲线、致死力和寿命期望曲线, 利用德氏多度分析方法分析了广东省阳春市八甲镇极小种群野生植物猪血木种群的年龄结构和动态, 并与2007年的研究结果进行对比, 分析该种群近10年的变化情况及其原因。结果表明: (1)研究区域内野生猪血木种群的数量变化动态指数(V_pi和V′_pi)均小于0, 存活曲线趋于Deevey-III型, 种群结构属于衰退型, 幼树数量丰富, 但由于向小树发展过程受阻, 种群无法及时更新补充。(2)存活曲线、致死力和寿命期待曲线一致显示在幼树、小树2级、中龄树2级这3个阶段, 出现阻碍因素, 影响种群的自然更新。(3)三甲镇猪血木幼苗减少了39.3%, 八甲镇猪血木幼苗锐减了71.9%, 三甲镇幼苗转化率较八甲镇低了近1/2。人为干扰是导致猪血木野生种群衰退的主要驱动因素, 已实施的保护策略并不适合当前情况下的野生猪血木种群。     

极小种群植物猪血木的种群现状及保护对策

猪血木(Euryodendron excelsum)是特产于中国的山茶科极危种, 但目前对导致猪血木种群结构改变的原因缺少相关的调查及研究, 保护策略不完善。该研究依据野外调查方法、编制标准生命表、存活曲线、致死力和寿命期望曲线, 利用德氏多度分析方法分析了广东省阳春市八甲镇极小种群野生植物猪血木种群的年龄结构和动态, 并与2007年的研究结果进行对比, 分析该种群近10年的变化情况及其原因。结果表明: (1)研究区域内野生猪血木种群的数量变化动态指数(V_pi和V′_pi)均小于0, 存活曲线趋于Deevey-III型, 种群结构属于衰退型, 幼树数量丰富, 但由于向小树发展过程受阻, 种群无法及时更新补充。(2)存活曲线、致死力和寿命期待曲线一致显示在幼树、小树2级、中龄树2级这3个阶段, 出现阻碍因素, 影响种群的自然更新。(3)三甲镇猪血木幼苗减少了39.3%, 八甲镇猪血木幼苗锐减了71.9%, 三甲镇幼苗转化率较八甲镇低了近1/2。人为干扰是导致猪血木野生种群衰退的主要驱动因素, 已实施的保护策略并不适合当前情况下的野生猪血木种群。     

猪血药用物质基础研究(Ⅰ)——脱色条件考察

利用粉末活性炭、羧甲基淀粉钠(CMS)、羧甲基纤维素钠(CMC)吸附作用进行中药猪血的脱色剂初步筛选,发现活性炭脱色效果较好;选取胃蛋白酶、胰蛋白酶、1394酶、木瓜蛋白酶4种酶酶解猪血蛋白,综合考虑胃蛋白酶酶解效果最好;进一步利用45均匀设计法得到猪血最佳酶解脱色条件为加酶量8%、温度45℃、酶解时间0.5 h、底物浓度18%,吸附剂为活性炭,脱色液呈浅黄色,无腥味,蛋白质含量较高,并且酶解后猪血蛋白分解为多肽,具有多功能生物活性。     

鸟类对猪血木种子的散布及在其保护中的意义

观察了广东八甲地区鸟类对猪血木种子的散布过程,对散布效果及其在幼苗建立、种群恢复以及保护生物学中的意义进行了分析。结果表明,猪血木种子通过鸟类和重力散布,但以鸟类散布为主;猪血木种子萌发的关键是种子能否从浆果暴露出来;鸟类对猪血木种子散布的意义在于破碎果实,暴露种子。由于人类活动的干扰,散布区内许多土地已异质化,一些种子被散布到无法萌发的环境中,限制了鸟类散布的效果。由于鸟类散布在猪血木幼苗建立和分布区扩张方面具有重要意义,因此在对猪血木进行保护时,除保护生境外还必须注意对鸟类进行保护。     

中国特有珍稀濒危植物猪血木的研究进展

对我国特有珍稀濒危植物猪血木的分类地位、资源现状及分布、生物学和生态学特性、发育生物学、保护遗传学、繁殖生物学、和濒危机制进行了综述,为该物种的种群恢复研究提供了参考.     

山茶科濒危植物猪血木的花器官发生

利用扫描电镜首次观察了山茶科极濒危植物猪血木(Euryodendron excelsum)的花器官发生过程。猪血木的花为两性完全花,萼片和花瓣均为2/5螺旋向心发生,单轮排列,且有逆时针和顺时针两种方式。雄蕊的形成是先形成一个环形分生组织,然后在环形分生组织上以2/5螺旋产生5束雄蕊原基,每一束雄蕊原基的第一雄蕊原基都是在对萼的位置产生,其它的雄蕊原基在其两侧产生。3心皮顺序发生,愈合成3室单子房,柱头平截不裂。猪血木与山茶亚科的花器官发生明显不同。     

动物血资源的利用

我国是世界上动物血资源最丰富的国家之一。据统计,每年约产猪血22万吨,牛血1万吨,羊血1.5万吨。目前除一小部分得到利用外,大部被废弃(尤其是大中城市)。大力开发利用我国的动物血资源可获得巨大的经济效益。目前,国内、外对动物血资源的利用主要有以下诸方面: 一、食品与饲料工业动物血含有丰富的蛋白质(16.4%-18.9%),其组成包括人体必需的全部八种必需氨基酸,赖氨酸和亮氨酸的含量尤高。还含有丰富的铁、钙、磷、镁、铜、锰、钾等元素,维生素(如B_(12),B_2),脂质和糖     

嗜热与嗜常温微生物的蛋白质氨基酸组成比较

嗜热微生物的嗜热特性与其蛋白质的高度热稳定性紧密相关。为了探索嗜热蛋白质的热稳定机制,比较嗜热和嗜常温微生物的蛋白质在氨基酸组成上的差别,收集110对分别来自嗜热和嗜常温微生物的同源蛋白质序列,比较两组蛋白质各种氨基酸含量以及疏水性氨基酸组成、疏水性指数和荷电氨基酸组成的差别,结果两者在多种氨基酸含量上存在微小但统计学上显著的差别,嗜热蛋白质比嗜常温蛋白质具有较高的平均疏水性和荷电氨基酸组成。对两组蛋白质的“脂肪族氨基酸指数”进行分析,证明嗜热蛋白质之所以具有较高的脂肪族氨基酸指数是由于其亮氨酸含量较高,与影响该指数的其它几种氨基酸无关;从而认为该指数的意义值得怀疑。通过对大量同源嗜热蛋白质和嗜常温蛋白质氨基酸组成的比较,能够揭示一些有关蛋白质热稳定性的普遍规律。     

肾综合征出血热病毒Gou3株M片段的分子特性及序列的比较分析

为测定我国肾综合征出血热病毒Ｇｏｕ３株的Ｍ片段全基因序列,了解该株分子基础,并分析其瑟其他病毒株的差异,将提取的感染了病毒的Ｖｅｒｏ－Ｅ６细胞总ＲＮＡ进行逆转录ＰＣＲ扩增,产物直接或纯化后克隆Ｔ载体并测定序列,结果测得Ｇｏｕ３株Ｍ片段的全基因序列共３６５１个核苷 ,最大读码框架从４７到３４４８,共编码１１３４个氨基酸。     

紫黑翼蚌钩介幼虫在不同规格寄主鱼寄生效果及对寄主鱼营养指标的影响

为提高紫黑翼蚌(Potamilus alatus)繁殖效率,探讨寄生对淡水石首鱼(Aplodinotus grunniens)营养指标的影响,实验通过比较钩介幼虫脱落数量,测试了不同规格寄主鱼的寄生效果,分析了寄生对寄主鱼血清生化指标及肌肉中氨基酸、脂肪酸含量的变化。结果显示:大规格组每尾鱼脱落数显著高于小规格组(P<0.05),小规格组每千克寄生鱼平均脱落稚贝数显著高于大规格组(P<0.05);寄生导致肌肉中肌酐显著升高(P<0.05),谷丙转氨酶、谷草转氨酶和乳酸脱氢酶显著降低(P<0.05),血糖、总蛋白、白蛋白、甘油三酯、总胆固醇、高密度脂蛋白和低密度脂蛋白与对照组无显著性差异(P>0.05);寄生组灰分与对照组无显著性差异(P>0.05),寄生组肌肉水分和粗脂肪含量显著高于对照组(P<0.05),粗蛋白显著低于对照组(P<0.05);寄生组天冬氨酸、丙氨酸、谷氨酸、酪氨酸、甘氨酸和精氨酸含量显著低于对照组(P<0.05),非必需氨基酸含量显著低于对照组(P<0.05),其他氨基酸之间无显著性差异(P>0.05)...     

Cloning, characterization, and genomic structure of the mouse Ikbkap gene.

Our laboratory recently reported that mutations in the human I-kappaB kinase-associated protein (IKBKAP) gene are responsible for familial dysautonomia (FD). Interestingly, amino acid substitutions in the IKAP correlate with increased risk for childhood bronchial asthma. Here, we report the cloning and genomic characterization of the mouse Ikbkap gene, the homolog of human IKBKAP. Like its human counterpart, Ikbkap encodes a protein of 1332 amino acids with a molecular weight of approximately 150 kDa. The Ikbkap gene product, Ikap, contains 37 exons that span approximately 51 kb. The protein shows 80% amino acid identity with human IKAP. It shows very high conservation across species and is homologous to the yeast Elp1/Iki3p protein, which is a member of the Elongator complex. The Ikbkap gene maps to chromosome 4 in a region that is syntenic to human chromosome 9q31.3. Because no animal model of FD currently exists, cloning of the mouse Ikbkap gene is an important first step toward creating a mouse model for FD. In addition, cloning of Ikbkap is crucial to the characterization of the putative mammalian Elongator complex.     

Lime treatment of keratinous materials for the generation of highly digestible animal feed: 2. Animal hair

Air-dried cow hair was treated using Ca(OH)(2) (insoluble in water but dissolved during reaction) at 100 degrees C. To obtain a liquid product rich in amino acids, a well-insulated, stirred reactor was used to perform the hydrolysis process for different time periods. High lime loadings and a long treatment period convert 70% of cow hair to soluble amino acids and polypeptides. Protein solubilization varies with lime loading especially for the long-term treatment (t>12h) showing that the hydroxyl group is required as a catalyst for the hydrolysis reaction and that lime is consumed during the process; as a consequence lower lime loading generate lower conversions. A very perceptible ammonia odor in the soluble product suggests amino acid degradation. Arginine, threonine, and serine are the more susceptible amino acids under alkaline hydrolysis. The amino acid composition of the solubilized product compares poorly with the essential amino acid requirements for various monogastric domestic animals, but it has value as ruminant feed.     

Structural determinants in substrate recognition by proton-amino acid symports in plasma membrane vesicles isolated from sugar beet leaves.

Amino acids are actively transported across the plasma membrane of plant cells by proton-coupled symports. Previously, we identified four amino acid symports in isolated plasma membrane vesicles, including two porters for the neutral amino acids. Here we investigated the effect of amino acid analogues on neutral amino acid transport to identify structural features that are important in molecular recognition by Neutral System I (isoleucine) and Neutral System II (alanine and leucine). D-Isomers of alanine and isoleucine were not effective transport antagonists of the L-isomers. These data are characteristic of stereospecificity and suggest that the positional relationship between the alpha-amino and carboxyl groups is an important parameter in substrate recognition. This conclusion was supported by the observation that beta-alanine and analogues with methylation at the alpha-carbon, at the carboxyl group, or at the alpha-amino group were not effective transport inhibitors. Specific binding reactions were also implicated in these experiments because substitution of the alpha-amino group with a space filling methyl or hydroxyl group eliminated transport inhibition. In contrast, analogues with various substitutions at the distal end of the amino acid were potent antagonists. Moreover, the relative activity of several analogues was influenced by the location of sidechain branches and Neutral Systems I and II were resolved based on differential sensitivity to branching at the beta-carbon. The kinetics of azaserine and p-nitrophenylalanine inhibition of leucine transport were competitive. We conclude that the binding site for the carboxyl end of the amino acid is a well-defined space that is characterized by compact, asymmetric positional relationships and specific ligand interactions. Although the molecular interactions associated with the distal portion of the amino acid were less restrictive, this component of the enzyme-substrate complex is also important in substrate recognition because the neutral amino acid symports are able to discriminate between specific neutral amino acids and exclude the acidic and basic amino acids.     

Random coil structures in bacterial proteins. Relationships of their amino acid compositions to flanking structures and corresponding genic base compositions

In this study we classified regions of random coil into four types: coil between alpha helix and beta strand, coil between beta strand and alpha helix, coil between two alpha helices and coil between two beta strands. This classification may be considered as natural. We used 610 3D structures of proteins collected from the Protein Data Bank from bacteria with low, average and high genomic GC-content. Relatively short regions of coil are not random: certain amino acid residues are more or less frequent in each of the types of coil. Namely, hydrophobic amino acids with branched side chains (Ile, Val and Leu) are rare in coil between two beta strands, unlike some acrophilic amino acids (Asp, Asn and Gly). In contrast, coil between two alpha helices is enriched by Leu. Regions of coil between alpha helix and beta strand are enriched by positively charged amino acids (Arg and Lys), while the usage of residues with side chains possessing hydroxyl group (Ser and Thr) is low in them, in contrast to the regions of coil between beta strand and alpha helix. Regions of coil between beta strand and alpha helix are significantly enriched by Cys residues. The response to the symmetric mutational pressure (AT-pressure or GC-pressure) is also quite different for four types of coil. The most conserved regions of coil are “connecting bridges” between beta strand and alpha helix, since their amino acid content shows less strong dependence on GC-content of genes than amino acid contents of other three types of coil. Possible causes and consequences of the described differences in amino acid content distribution between different types of random coil have been discussed.     

Molecular cloning of the E1 beta subunit of the rat branched chain alpha-ketoacid dehydrogenase.

We determined the cDNA sequence of the mRNA for antithrombin III (AT III) from sheep liver. It encodes a protein of 465 amino acids, including a signal peptide of 32 amino acids. The amino acid sequence of the mature protein shows a sequence identity of 89.1%, 95.6% and 85.0% to the human, bovine and rabbit equivalents, respectively. Cysteine residues involved in disulfide bonds as well as potential glycosylation sites are conserved between the four species. In contrast, the amino acid sequence of the signal peptide shows a smaller identity, i.e., 68.7% and 56.3% compared to the human and rabbit preprotein, respectively.     

A Protein Hydrolysate Enzymatically Produced from the Industrial Waste of Processing Icelandic Scallop Chlamys islandica

Dry hydrolysate was prepared from protein-containing waste of Icelandic scallop processing by means of a proteinase complex from king crab hepatopancreas. The resulting product contains no less than 80% free amino acids and oligopeptides. Predominant are aspartic acid, leucine, isoleucine, arginine, and lysine, which account for more than 50% of the free amino acids. The potential of using the protein hydrolysate as a nutrient for microorganism cultivation is estimated. It is demonstrated that the hydrolysate can be used for growing test cultures.