Lindner H, Höpfner S, Täfler-Naumann M, Miko M, Konrad L, Röhm K H
Institute of Physiological Chemistry, School of Medicine, Philipps-University, Institute of Physiological Chemistry, Karl von Frisch Strasse 1, 35033, Marburg, Germany.
Biochimie. 2000 Feb;82(2):129-37. doi: 10.1016/s0300-9084(00)00191-7.
Aminoacylase I (Acy-1, EC 3.5.1.14) is found in many mammalian tissues, with highest activities occurring in kidney. The enzyme hydrolyzes a variety of N-acylated amino acids; however, the physiological role and the exact cellular localization of Acy-1 are still a matter of debate. The comparison of Acy-1 activities in kidney and liver homogenates of 11 mammalian species showed that the enzyme is most abundant in true herbivores such as sheep and cattle as well as in omnivores, while activities were very low in both rodents and the cat. Acy-1 activity was not detected in livers of dogs of five different breeds. Using in situ hybridization of porcine kidney sections with DIG-labeled RNA probes, Acy-1 mRNA was shown to be evenly distributed throughout the tubular system, while glomeruli and the interstitium were free of stain. During subcellular fractionation, porcine Acy-1 behaved like a typical cytosolic enzyme. Commonly, Acy-1 is thought to catalyze hydrolytic reactions, i.e., the formation of free amino acids from acylated derivatives. Based on the present results and literature data, we propose a novel hypothesis, i.e., that Acy-1 catalyzes the synthesis (rather than the hydrolysis) of hippurate that is formed as a detoxification product of aromatic compounds.
氨基酰化酶I（Acy-1，EC 3.5.1.14）存在于许多哺乳动物组织中，在肾脏中的活性最高。该酶可水解多种N-酰化氨基酸；然而，Acy-1的生理作用和确切的细胞定位仍存在争议。对11种哺乳动物肾脏和肝脏匀浆中Acy-1活性的比较表明，该酶在绵羊和牛等真正的食草动物以及杂食动物中含量最高，而在啮齿动物和猫中活性都很低。在五个不同品种的狗的肝脏中未检测到Acy-1活性。使用地高辛标记的RNA探针与猪肾切片进行原位杂交，结果显示Acy-1 mRNA在整个肾小管系统中均匀分布，而肾小球和间质则无染色。在亚细胞分级分离过程中，猪Acy-1表现得像一种典型的胞质酶。通常认为，Acy-1催化水解反应，即从酰化衍生物形成游离氨基酸。基于目前的结果和文献数据，我们提出了一个新的假设，即Acy-1催化马尿酸盐的合成（而非水解），马尿酸盐是芳香族化合物解毒产物。
