毒理性
在患有遗传性代谢错误(IEM)称为阿尔kaptonuria的患者的体内发现了极高的尿黑酸水平。尿黑酸会自发地氧化成苯醌醋酸(BQA),后者会聚合形成血浆可溶性黑色素(PSM)。PSM会使许多组织变黑(石黄色变 - 因为组织看起来像赭石),并在软骨和其他结缔组织、关节、血管、心脏瓣膜和肾脏中产生广泛的退行性变化。石黄色变的组织既僵硬又不寻常地脆弱。PSM在软骨细胞(形成软骨的细胞)中的积累导致细胞防御、蛋白质折叠和细胞组织中的蛋白质水平发生深刻变化。在阿尔kaptonuria患者的软骨细胞中,蛋白质的翻译后氧化增加,特别是高分子量蛋白聚集体,表现得尤为明显。
Extremely high levels of homogentisic acid are found in patients with the inborn error of metabolism (IEM) called Alkaptonuria. Homogentisic acid spontaneously undergoes oxidation into benzoquinone acetic acid (BQA), which polymerizes forming plasma soluble melanins (PSM). The PSM darkens many tissues (ochronosis - as the tissue looks like ochre), and produces widespread degenerative changes in cartilage and other connective tissues, joints, blood vessels, heart valves and the kidneys. Ochronotic tissue is stiff and unusually brittle. The accumulation of PSM in chondrocytes (the cells that form cartilage) leads to profound alterations in the levels of proteins involved in cell defense, protein folding, and cell organization. An increased post-translational oxidation of proteins, which also involved high molecular weight protein aggregates, has been found to be particularly evident in chondrocytes from patients with alkaptonuria.
来源:Toxin and Toxin Target Database (T3DB)