Orientation of the peptide formation of N-phosphoryl amino acids in solution

The peptide formation of N-phosphoryl amino acids with amino acids proceeds in aqueous solution without any coupling reagents. After being separated in sephadex gel column, the phosphoryl dipeptides were analyzed by the electrospray ionization tandem mass spectrometry (ESIMS/ MS). The result demonstrates that phosphoryl dipeptides were detected in all the reaction systems. It is found that the formation of N-phosphoryl dipeptides is oriented: the N-terminal amino acid residues of the N-phosphoryl dipeptides are from N-phosphoryl amino acids, and the peptide elongation happened at the C-terminal. Only a-dipeptide, no b-dipeptide, is formed in the N-phosphoryl dipeptides, showing that a-carboxylic group is activated selectively by N-phosphorylation. Theoretical calculation shows that the peptide formation of N-phosphoryl amino acids might happen through a penta-coordinate carboxylic-phosphoric intermediate in solution. These results might give some clues to the study on the origin of proteins and protein biosynthesis.     

Orientation of the peptide formation of N-phosphoryl amino acids in solution

The peptide formation of N-phosphoryl amino acids with amino acids proceeds in aqueous solution without any coupling reagents. After being separated in sephadex gel column, the phosphoryl dipeptides were analyzed by the electrospray ionization tandem mass spectrometry (ESIMS/ MS). The result demonstrates that phosphoryl dipeptides were detected in all the reaction systems. It is found that the formation of N-phosphoryl dipeptides is oriented: the N-terminal amino acid residues of the N-phosphoryl dipeptides are from N-phosphoryl amino acids, and the peptide elongation happened at the C-terminal. Only a-dipeptide, no β-dipeptide, is formed in the N-phosphoryl dipeptides, showing that a-carboxylic group is activated selectively by N-phosphorylation. Theoretical calculation shows that the peptide formation of N-phosphoryl amino acids might happen through a penta-coordinate carboxylic-phosphoric intermediate in solution. These results might give some clues to the study on the origin of proteins and protein biosynthesis.     

二肽衍生物的非水毛细管电泳分离

以1,2-苯并-3,4二氢咔唑-9-乙基氯甲酸酯(BCEOC)作为柱前衍生试剂,利用非水毛细管区带电泳法对衍生二肽进行分离,考察了该试剂用于非水毛细管区带电泳模式分离的几个关键条件,在有机溶剂甲醇与乙腈比例75∶25(V/V),醋酸铵浓度45 mmol/L,醋酸浓度0.8 mol/L,柱温17℃,分离电压28 kV条件下,采用二极管阵列检测,实现了11种二肽的基线分离.     

Evolution of exocrine chemical defense in leaf beetles (Coleoptera: Chrysomelidae)

Summary In this review we speculate on possible scenarios for the evolution of the very high diversity in chemical compounds liberated by exocrine glands of adults Chrysomelidae. Shift in host plant affinities and subsequent adaptation of the beetles to the plant toxins strongly influence the nature of the beetles' chemical defense.     

小肽不同高效液相色谱柱前衍生化反应的实验研究

分别用氯甲酸-9-芴基甲酯(9-fluorenylmethylchloroformate,FMOC-Cl)、9-芴基甲氧基甲酸琥珀酰亚胺类酯(9-fluorenylmethoxy carbonyl succinimide,FMOC-OSU)和丹磺酰氯(1-dimethylaminonaphthalene-5-sulfonyl-chloride,Dns-Cl)为衍生化试剂对小肽进行了衍生化反应.研究和比较了各种衍生试剂用量、衍生缓冲体系pH条件、衍生化时间等因素对衍生反应的影响及衍生产物的稳定性.结果发现,FMOC-Cl对肽的衍生反应速度快,衍生反应完全,衍生产物稳定.     

红树林内源真菌2524号的肽类成分(Ⅰ)

采自香港的红树林内源真菌 (No 2 5 2 4)能产生丰富的肽类代谢产物 ,从培养液的乙酸乙酯提取物中分离出 5个环二肽 :环 (酪_亮 )二肽 ,环 (苯丙_丙 )二肽 ,环 (丙_缬 )二肽 ,环 (脯_甘 )二肽和 5_异丁基_2 ,4_二酮咪唑烷。它们的结构通过IR ,FABMS ,NMR以及 2DNMR得到确定     

生物活性环二肽研究进展

在对近年来活性环二肽的发现及其合成策略进行了综述的基础上,指出环二肽在自然界及天然产物中广泛存在,由于其结构特殊,使得环二肽成为药物化学中一个重要的药效团,许多环二肽具有强的生理活性．     

南海红树林内生真菌1893代谢产物研究

对采自香港的红树林内生真菌（1893号）的代谢产物进行了研究。共分离得到10个化合物，其中5-对羟基苯乙基-2，4-咪唑烷二酮和尿囊素是首次从海洋真菌中分离得到，它们的结构通过IR，FABMS，NMR及2D-NMR得到确定。