Zwitterionic reagents for labeling, cross-linking and improving the performance of chemiluminescent immunoassays
作者:Anand Natrajan、David Sharpe、David Wen
DOI:10.1039/c2ob06807a
日期:——
Improving reagent performance in immunoassays both to enhance assay sensitivity and to minimize interference are ongoing challenges in clinical diagnostics. We describe herein the syntheses of a new class of hydrophilic reagents containing sulfobetaine zwitterions and their applications. These zwitterionic reagents are potentially useful for improving the properties of immunoassay reagents. We demonstrate
Mechanism study on the Oligomerization of Amino Acids into Peptides by Phosphorus Trichloride
作者:Wenjie Zhao、Dongxin Zhao、Kui Lu
DOI:10.1080/10426500701807467
日期:2008.1.14
As treated by phosphorustrichloride, amino acids could oligomerize into polypeptides. Based on the results obtained by 31P-NMR and ESI-MS/MS, a possible reaction mechanism was proposed. The mechanism might undergo a penta-coordinated phosphorus intermediat. The activated amino acid was a five-membered cyclic penta-coordinated phosphorus intermediate. The nucleophilic attack of the amino group from
A Novel<scp>L</scp>-Amino Acid Ligase from<i>Bacillus subtilis</i>NBRC3134 Catalyzed Oligopeptide Synthesis
作者:Kuniki KINO、Toshinobu ARAI、Daisuke TATEIWA
DOI:10.1271/bbb.90649
日期:2010.1.23
l-Amino acid ligase catalyzes dipeptide synthesis from unprotected l-amino acids in an ATP-dependent manner. We have purified a new l-amino acid ligase, RizA, which synthesizes dipeptides whose N-terminus is Arg, from Bacillus subtilis NBRC3134, a microorganism that produces a rhizocticin peptide antibiotic. It was suggested that RizA is probably involved in rhizocticin biosynthesis. In this study, we performed sequence analysis of unknown regions around rizA, and newly identified a gene that encodes a protein that possesses an ATP-grasp motif upstream of rizA. This gene was designated rizB, and its recombinant protein was prepared. Recombinant RizB synthesized homo-oligomers of branched-chain l-amino acids and l-methionine consisting of two to five amino acids in an ATP-dependent manner. RizB also synthesized various heteropeptides. Further examination showed that RizB might elongate a peptide chain at the N-terminus. This is the first report on an l-amino acid ligase catalyzing oligopeptide synthesis.
l-氨基酸连接酶以一种 ATP 依赖性方式催化未受保护的 l-氨基酸合成二肽。我们从生产根肿灵多肽抗生素的枯草芽孢杆菌 NBRC3134 中纯化出一种新的 l-氨基酸连接酶 RizA,它能合成 N 端为 Arg 的二肽。有研究认为,RizA 可能参与了根皮素的生物合成。在本研究中,我们对 rizA 周围的未知区域进行了序列分析,新发现了一个编码具有 ATP 抓取基序的蛋白质的基因,该基因位于 rizA 的上游。该基因被命名为 rizB,并制备了其重组蛋白。重组 RizB 以 ATP 依赖性方式合成由 2 至 5 个氨基酸组成的支链 l-氨基酸和 l-蛋氨酸的同源异构体。RizB 还能合成各种杂肽。进一步研究表明,RizB 可能会在 N 端延长肽链。这是首次报道一种催化寡肽合成的 l-氨基酸连接酶。
The Juliá-Colonna Asymmetric Epoxidation Reaction of Chalcone Catalyzed by Length Defined Oligo-<b>L</b>-leucine: Importance of the<b><i>N</i></b>-Terminal Functional Group and Helical Structure of the Catalyst in the Asymmetric Induction
oligo-L-leucine, for the Julia-Colonnaasymmetricepoxidation of chalcone with defined degrees of polymerization were prepared by a stepwise elongation method. The yield and enantioselectivity in the epoxidation increased with the degree of polymerization of the catalyst. The presence of an unprotected amine moiety at the N-terminus proved to be essential for high asymmetric induction. The IR characteristic
通过逐步延伸法制备用于具有确定聚合度的查耳酮的 Julia-Colonna 不对称环氧化反应的催化剂低聚-L-亮氨酸。环氧化反应的产率和对映选择性随着催化剂聚合度的增加而增加。N-末端未保护的胺部分的存在证明对于高不对称诱导是必不可少的。催化剂的 IR 特征吸收带(酰胺 I 区)表明催化剂中的螺旋结构与不对称诱导有关。
Cyclic Penta- and Hexaleucine Peptides without <i>N</i>-Methylation Are Orally Absorbed
作者:Timothy A. Hill、Rink-Jan Lohman、Huy N. Hoang、Daniel S. Nielsen、Conor C. G. Scully、W. Mei Kok、Ligong Liu、Andrew J. Lucke、Martin J. Stoermer、Christina I. Schroeder、Stephanie Chaousis、Barbara Colless、Paul V. Bernhardt、David J. Edmonds、David A. Griffith、Charles J. Rotter、Roger B. Ruggeri、David A. Price、Spiros Liras、David J. Craik、David P. Fairlie
DOI:10.1021/ml5002823
日期:2014.10.9
peptide-based drugs has been severely limited by lack of oral bioavailability with less than a handful of peptides being truly orally bioavailable, mainly cyclic peptides with N-methyl amino acids and few hydrogen bond donors. Here we report that cyclic penta- and hexa-leucine peptides, with no N-methylation and five or six amide NH protons, exhibit some degree of oral bioavailability (4–17%) approaching that