Yoshida N, Sakai Y, Isogai A, Fukuya H, Yagi M, Tani Y, Kato N
Department of Agricultural Chemistry, Faculty of Agriculture, Kyoto University, Japan.
Eur J Biochem. 1996 Dec 15;242(3):499-505. doi: 10.1111/j.1432-1033.1996.0499r.x.
Fructosyl amino acid oxidase (FAOD), which is active toward model compounds of the glycated proteins in blood, N epsilon-fructosyl N sigma-Z-lysine and N-fructosyl valine, was purified to homogeneity from Aspergillus terreus GP1. Though the enzyme did not use glycated proteins directly as its substrate, it used glycated human serum albumin (HSA) when HSA was treated with a protease. Linear relationships between both the concentration and the increase in absorbance and the glycation rate of glycated HSA and the increase in absorbance were observed. cDNAs coding for FAODs were cloned from cDNA libraries of A. terreus GP1 and Penicillium janthinellum AKU 3413. The coding region for both fungal FAODs consisted of 1314 bp encoding 437 amino acids. The sequence of a dinucleotide-binding motif, GXGXXG, was in the deduced N-terminal region and a similar sequence to that the active site of bacterial sarcosine oxidases was found near the C-terminal region of FAOD. The of C-terminal tripeptides SKL and AKL of FAODs from A. terreus and P. janthinellum, respectively, represent typical peroxisomal-targeting signals. Finally, FAOD protein was produced in Escherichia coli transformants in an active form, and at the same level as in the original fungi.
果糖基氨基酸氧化酶（FAOD）对血液中糖化蛋白的模型化合物Nε-果糖基-Nσ-Z-赖氨酸和N-果糖基缬氨酸具有活性，它是从土曲霉GP1中纯化至同质的。尽管该酶不直接将糖化蛋白用作底物，但当糖化人血清白蛋白（HSA）用蛋白酶处理时，它可以利用糖化HSA。观察到糖化HSA的浓度与吸光度增加之间以及糖化率与吸光度增加之间均呈线性关系。从土曲霉GP1和展青霉AKU 3413的cDNA文库中克隆了编码FAOD的cDNA。两种真菌FAOD的编码区均由1314 bp组成，编码437个氨基酸。二核苷酸结合基序GXGXXG的序列位于推导的N端区域，并且在FAOD的C端区域附近发现了与细菌肌氨酸氧化酶活性位点相似的序列。土曲霉和展青霉的FAOD的C端三肽分别为SKL和AKL，代表典型的过氧化物酶体靶向信号。最后，FAOD蛋白在大肠杆菌转化体中以活性形式产生，且产量与原始真菌中的水平相同。
