Ala-Pro-p-nitroaniline

• 分子结构分类: 有机化合物 - 有机酸及其衍生物 - 羧酸及其衍生物
• 英文名称: Ala-Pro-p-nitroaniline
• 英文别名: 1-(2-aminopropanoyl)-N-(4-nitrophenyl)pyrrolidine-2-carboxamide
• 化学式: C₁₄H₁₈N₄O₄
• 分子量: 306.321
• InChiKey: WUOZBACYMYYTOQ-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  0.7
• 重原子数：
  22
• 可旋转键数：
  3
• 环数：
  2.0
• sp3杂化的碳原子比例：
  0.43
• 拓扑面积：
  121
• 氢给体数：
  2
• 氢受体数：
  5

反应信息

• 作为反应物：
  描述：

  Ala-Pro-p-nitroaniline 在 sodium chloride 作用下， 以 phosphate buffer 为溶剂， 生成 4-硝基苯胺 、 (9CI)-六氢-3-甲基吡咯并[1,2-a]吡嗪-1,4-二酮
  参考文献：
  名称：

  Kinetics of Diketopiperazine Formation Using Model Peptides

  摘要：

  The intramolecular aminolysis of Phe-Pro-p-nitroaniline (Phe-Pro-pNA) to Phe-Pro-diketopiperazine (Phe-Pro-DKP) was studied as a function of pH, temperature, buffer concentration, and buffer species using an HPLC assay that permits simultaneous analysis of the disappearance of the starting material and the appearance of degradation products. The degradation followed pseudo-first-order kinetics and showed significant dependence on pH. Phosphate (pH 5-8) and glycine (pH 9-10) buffers exhibit general base catalysis. The pH-rate profile suggested that the rate of Phe-Pro-DKP formation depends on the degree of ionization of the N-terminal amino group, with the unprotonated reactant being more reactive than the protonated form. The pK(a) value of 6.1, determined kinetically, and three microscopic rate constants were adequate to describe the shape of the pH-rate profile. In the pH range studied, Phe-Pro-DKP was the only product generated upon degradation of Phe-Pro-pNA. At pH values between 3 and 8, Phe-Pro-DKP was stable, while at pH less than 3 and greater than 8 it undergoes hydrolysis to the dipeptide, Phe-Pro-OH. Sequence inversion, a reaction normally associated with DKP formation, was not observed. The influence of primary sequence on the formation of DKP was also investigated using X-Pro-pNA analogues, where X = Gly, Ala, Val, Phe, beta-cyclohexylalanine, and Arg. Changing the amino acid preceding the proline residue had a significant effect on the rate of DKP formation at pH 7.0.

  DOI：

  10.1021/js970325m

文献信息

• Kinetics of Diketopiperazine Formation Using Model Peptides
  作者：Chimanlall Goolcharran、Ronald T. Borchardt

  DOI：10.1021/js970325m

  日期：1998.3

  The intramolecular aminolysis of Phe-Pro-p-nitroaniline (Phe-Pro-pNA) to Phe-Pro-diketopiperazine (Phe-Pro-DKP) was studied as a function of pH, temperature, buffer concentration, and buffer species using an HPLC assay that permits simultaneous analysis of the disappearance of the starting material and the appearance of degradation products. The degradation followed pseudo-first-order kinetics and showed significant dependence on pH. Phosphate (pH 5-8) and glycine (pH 9-10) buffers exhibit general base catalysis. The pH-rate profile suggested that the rate of Phe-Pro-DKP formation depends on the degree of ionization of the N-terminal amino group, with the unprotonated reactant being more reactive than the protonated form. The pK(a) value of 6.1, determined kinetically, and three microscopic rate constants were adequate to describe the shape of the pH-rate profile. In the pH range studied, Phe-Pro-DKP was the only product generated upon degradation of Phe-Pro-pNA. At pH values between 3 and 8, Phe-Pro-DKP was stable, while at pH less than 3 and greater than 8 it undergoes hydrolysis to the dipeptide, Phe-Pro-OH. Sequence inversion, a reaction normally associated with DKP formation, was not observed. The influence of primary sequence on the formation of DKP was also investigated using X-Pro-pNA analogues, where X = Gly, Ala, Val, Phe, beta-cyclohexylalanine, and Arg. Changing the amino acid preceding the proline residue had a significant effect on the rate of DKP formation at pH 7.0.