Umeda H, Takeuchi M, Suyama K
Department of Applied Bioorganic Chemistry, Division of Life Science, Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555, Japan.
J Biol Chem. 2001 Apr 20;276(16):12579-87. doi: 10.1074/jbc.M009744200. Epub 2001 Jan 19.
Isolation and structure analysis of two amino acids from bovine ligamentum nuchae elastin hydrolysates revealed the presence of pyridine cross-links in elastin. The structures of these amino acids were determined to have 3,4,5- and 2,3,5-trisubstituted pyridine skeletons both with three carboxylic acids and a mass of 396 (C(18)H(28)N(4)0(6)) identified as 4-(4-amino-4-carboxybutyl)-3,5-di-(3-amino-3-carboxypropyl)-pyridine and 2-(4-amino-4-carboxybutyl)-3,5-di-(3-amino-3-carboxypropyl)-pyridine. We have named these pyridine cross-links desmopyridine (DESP) and isodesmopyridine (IDP), respectively. Structure analysis of these pyridine cross-links implied that the formation of these cross-links involved the condensation reaction between ammonia and allysine. The elastin incubated with ammonium chloride showed that DESP and IDP levels increased as the allysine content decreased. DESP and IDP were measured by high pressure liquid chromatography (HPLC) with UV detection and were found in a variety of bovine tissues. The DESP/desmosine (DES) and IDP/isodesmosine (IDE) ratios in aorta elastin were higher than in other tissues. DESP and IDP contents in human aorta elastin were found to be gradually increased with age. The concentration of IDP was significantly elevated in aorta elastin of rat with chronic liver cirrhosis induced by carbon tetrachloride (mean +/- S.D.; 11.1 +/- 0.9 nmol/mg elastin) when compared with normal rats (5.9 +/- 1.5 nmol/mg elastin). Although DESP and IDP are present at only trace concentrations in the tissue elastin, these pyridine cross-links may be useful biomarkers for the aortic elastin damaged by ammonia.
从牛项韧带弹性蛋白水解产物中分离并分析两种氨基酸，结果显示弹性蛋白中存在吡啶交联结构。经测定，这两种氨基酸的结构具有3,4,5 - 和2,3,5 - 三取代吡啶骨架，均带有三个羧酸基团，分子量为396（C₁₈H₂₈N₄O₆），分别鉴定为4 - (4 - 氨基 - 4 - 羧基丁基)-3,5 - 二(3 - 氨基 - 3 - 羧基丙基)-吡啶和2 - (4 - 氨基 - 4 - 羧基丁基)-3,5 - 二(3 - 氨基 - 3 - 羧基丙基)-吡啶。我们分别将这些吡啶交联结构命名为去甲吡啶交联（DESP）和异去甲吡啶交联（IDP）。对这些吡啶交联结构的分析表明，这些交联结构的形成涉及氨与烯赖氨酸之间的缩合反应。用氯化铵孵育弹性蛋白后发现，随着烯赖氨酸含量的减少，DESP和IDP水平升高。采用带紫外检测的高压液相色谱法（HPLC）测定DESP和IDP，结果在多种牛组织中均有发现。主动脉弹性蛋白中的DESP/锁链素（DES）和IDP/异锁链素（IDE）比值高于其他组织。研究发现，人主动脉弹性蛋白中DESP和IDP的含量随年龄增长而逐渐增加。与正常大鼠（5.9±1.5 nmol/mg弹性蛋白）相比，四氯化碳诱导的慢性肝硬化大鼠主动脉弹性蛋白中IDP的浓度显著升高（平均值±标准差；11.1±0.9 nmol/mg弹性蛋白）。尽管DESP和IDP在组织弹性蛋白中仅以痕量浓度存在，但这些吡啶交联结构可能是氨损伤主动脉弹性蛋白的有用生物标志物。
