Non-enzymatic glycosylation of proteins in biological sytem and its physiological significance in aging process.

蛋白质与葡萄糖的非酶糖基化称为美拉德反应，通过希夫碱加合物和阿马多里重排产物，产生具有荧光、棕色和交联特性的高级糖基化终产物 (AGE)。通过美拉德反应进行体内蛋白质修饰。尽管我们对 AGE 蛋白的化学结构一无所知，但据信特别是年龄产物在糖尿病并发症或衰老过程中发挥着重要作用。在本项目中，我们阐明了 AGE 产品的生物学特性。还尝试确定 AGE-产物的化学结构。得到如下结果： 1． AGE-蛋白如AGE-白蛋白和AGE-血红蛋白经历受体介导的巨噬细胞或巨噬细胞衍生细胞的内吞作用，包括大鼠肝窦细胞、大鼠和小鼠腹膜巨噬细胞以及人单核巨噬细胞。该受体与我们于1986.2发现的醛修饰蛋白的清道夫受体相同。塞拉米等人。声称2-(2-呋喃酰基)-4(5)-(呋喃基)-1H-咪唑(FFI)参与受体识别。然而，我们使用合成的FFI衍生物的实验清楚地表明情况并非如此。3．使用抗FFI抗体的放射免疫测定和高效液相色谱法的测定表明，FFI实际上是AGE蛋白酸水解以及随后与氨反应后产生的伪影，这是反对FFI体内存在的证据。4。主要荧光化合物是从 AGE-1-赖氨酸衍生物中分离出来的。免疫学分析表明，这种荧光化合物确实出现在衰老蛋白中。其精确的化学结构正在确定中。以上结果综合表明，AGE 蛋白的共同结构可能对于清道夫受体的生物识别至关重要。

Nonenzymatic glycosylation of proteins with glucose named the Maillard reaction leads, through a Schiff base adduct and Amadori rearrangement products, to advanced glycosylation end product (AGE) with fluorescence, brown color and cross-linked property. Protein modification in vivo by the Maillard reaction. Particularly age-products, is believed to play an important role in deabetic complications or aging processes, although nothing is known about a chemical structure(s) of AGE-proteins. In the present project, we elucidated the biological property of AGE-products. An attempt was also made to determine the chemical structure of AGE-product(s). Following results were obtained.1. AGE-proteins such as AGE-albumin and AGE-hemoglobin underwent receptor-mediated endocytosis by macrophages or macrophage-derived cells, including rat sinusoidal liver cells, rat and murine peritoneal macrophages and human monocyte macrophages. The receptor was found to be identical to a scavenger receptor for aldehyde-modified proteins which had been discovered by us in 1986.2. Cerami et al. claimed that 2-(2-furoyl)-4(5)-(furanyl)-1H-imidazole (FFI) was involved in the recepter recognition. However, our experiment using synthesized FFI derivatives clearly showed that this was not the case.3. Determination by the radioimmunoassay using an anti-FFI antibody and by high performance liquid chromatography demonstrated that FFI was in fact an artifact generated after acid hydrolysis of AGE-proteins and subsequent reaction with ammonia, evidence against in vivo presence of FFI.4. The major fluorescent compound was isolated from AGE-l-lysine derivatives. Immunological analyses indicated that this fluorescent compound did occur to age-proteins. Its precise chemical structure is being determined.The above results taken together suggest that a structure in common among AGE-proteins might be crucial to the biological recognition by the scavenger receptor.