Isolation and structure of a novel C-terminally amidated opioid peptide, amidorphin, from bovine adrenal medulla

Biologically active peptide hormones and neurotransmitters have been shown to be enzymatically liberated from larger, inactive precursor molecules by tissue-specific post-translational processing, particularly at the typical cleavage signals of paired basic residues. Subsequent N-terminal or C-terminal modifications may be of importance in regulating the biological activities of these peptides. C-terminal alpha-amidation is considered to be essential for the biological function of several non-opioid peptides. Here we present the isolation and structure of a novel C-terminally amidated opioid peptide, amidorphin, from bovine adrenal medulla. Amidorphin and the recently isolated octapeptide metorphamide (adrenorphin) are the only endogenous opioid peptides in mammals known to possess a C-terminal amide group. The amino acid sequence of amidorphin corresponds to the sequence 104-129 of bovine proenkephalin A. Very high concentrations of amidorphin were detected in bovine adrenal medulla and in a further endocrinological system, the hypothalamic-neurohypophyseal axis. Amidorphin may therefore be considered to be a major gene product of the opioid peptide precursor proenkephalin A in these endocrine tissues.     

牛乳腺上皮细胞的快速分离和培养

以西门塔尔肉牛为材料,采集已被屠宰的奶牛乳腺组织,利用机械剪切组织块及胶原酶消化的方法,在体外进行原代乳腺上皮细胞分离和培养.结果发现,组织块接种法成功地培养出原代乳腺上皮细胞,而胶原酶消化法没有成功.研究表明,组织块接种法是一种简便快速的牛乳腺细胞培养方法,经数次传代后,细胞增殖依旧旺盛.     

羊栖菜多糖分离纯化和结构的初步鉴定

将提取的羊栖菜多糖用sevage法除蛋白、H2O2脱色后得到羊栖菜多糖半纯品,依次通过DE-AE-52、Sephadex G-200柱层析分离纯化后得到SFPS-B2、SFPS-C1、SFPS-D2三个多糖组分,用Sephacryl S200-HR柱层析鉴定纯度,三种组分的多糖为均一多糖,质量分数分别为86.02%、81.05%、86.95%.对SFPS-D2进行结构初步研究,通过紫外光谱、红外光谱和毛细管电泳分析,结果表明SFPS-D2不含蛋白质和核酸,多糖组成以β构型的吡喃糖苷键为主,含有硫酸基-O-SO3,其单糖组成以木糖、葡萄糖和半乳糖为主,其比例为木糖∶葡萄糖∶半乳糖=3.45∶5.8∶1.     

Isolation, purification and characterization of secondary structure of antifreeze protein fromAmmopiptanthus mongolicus

Antifreeze protein (AFP) from Ammopiptanthus mongolicus leaves was isolated and purified with DEAE cellulose 52, Sephacryl 300, heat treatment and preparative isotachophoresis. The molecular weight of AFP was 50 ku by SDS-PAGE measurement. The average thermal hysteresis activity (THA) of AFP was 0.35℃ at 5 mg/mL using a differential scanning calorimeter (DSC). This AFP showed heated stability. From circular dichroism (CD) of AFP spectral data from 195—240 nm, a well-defined secondary structure of 11% a-helix, 34% antiparallel b-sheet and 55% random coil for the plant AFP was deduced.     

The covalent and tertiary structure of bovine liver rhodanese

Bovine liver rhodanese is a single polypeptide of 293 amino acids in which the halves of the molecule assume analogous tertiary structures in the absence of substantial sequence homology. The sulphur atom transferred during catalysis is bound in persulphide linkage to Cys-247. Substrate binding seems to involve Arg-186 and Lys-249.     

两个基于5-（3-氨基苯基）-四唑配体的双核金属配合物：合成、结构与荧光性质

通过水热方法合成2个基于5-（3-氨基苯基）四唑（apt-）配体的金属配合物[Pb2（phen）2（H2O）2（apt）4]（Ⅰ）和[Zn2（phen）2（apt）2（N3）2]·H2O（Ⅱ）,并进行结构表征和荧光性能的测定.结构研究表明：2个配合物均呈现双核的分子结构,其中配合物Ⅰ中1对apt-离子连接2个独立的PbⅡ八面体,配合物Ⅱ则由2个对称的叠氮离子连接2个中心对称的ZnⅡ离子,2个双核分子进一步通过氢键作用拓展形成二维超分子层.此外,2个配合物均具有良好的热稳定性且表现出由金属到配体电荷转移的荧光发射峰,表明其在荧光材料中具有潜在的应用前景.     

混合钼钒多金属氧酸盐的水热合成、结构表征及磁性研究

通过水热方法合成了一种混合钼钒多金属氧酸盐[Cu(phen)_2]_4{HPMo_8~Ⅵ V_6~ⅣO_(42)[Cu(phen)]_2}·2H_2O.采用X射线单晶衍射、元素分析、红外光谱对其进行了表征,同时对其磁学性质进行了研究.结果表明:标题化合物包含高度还原的二帽假Keggin结构的多氧阴离子支撑2个过渡金属配合物,即铜配合物阳离子[Cu(phen)_2]~+和结晶水;该化合物呈铁磁性相互作用.     

Isolation and structure of a human fibroblast interferon gene

Chimaeric plasmids containing double-stranded cDNA copies of mRNA induced in human fibroblasts by poly I . C were screened by an RNA selection method. A series of clones to which human fibroblast interferon mRNA selectively hybridized was identified. From the nucleotide sequence of the gene, the complete amino acid sequence of human fibroblast interferon was deduced. The protein is 166 amino acids long and is preceded by a 21-amino acid signal sequence.