Saraswathi M, Nakanishi T, Shimizu A
Department of Clinical Pathology, Osaka Medical College, 2-7 Daigaku-cho, Takatsuki-city, Osaka 569-8686, Japan.
Biochim Biophys Acta. 1999 Feb 2;1426(3):483-90. doi: 10.1016/s0304-4165(98)00171-8.
Electrospray ionization mass spectrometry (ESIMS) was used for relative quantification of glycated Cu-Zn superoxide dismutase (SOD-1) in human erythrocytes. SOD-1 samples were prepared from erythrocytes by removing hemoglobin using hemoglobind gel followed by ethanol and chloroform extraction. The reproducibility in measurement of the relative percentage of glycated protein was good, and the standard deviation of each measurement was 4.0%. From the mass spectral analysis of a mixture of commercial SOD-1 and in vitro partially glycated SOD-1 in several ratios, it was found that free and glycated SOD-1 have the same ionization efficiencies. The percentage of glycation on SOD-1 was measured in 30 individuals, including patients with diabetes mellitus. The glycation levels ranged from 4.5% to below the detection limit. The SOD-1 sample extracted from erythrocytes was fractionated by Glyco-Gel B chromatography, and the separated fractions were analyzed by MS. The mass spectra of absorbed fraction showed significant amounts of non-specific binding of non-glycated proteins to Glyco-Gel B.
采用电喷雾电离质谱法（ESIMS）对人红细胞中糖化铜锌超氧化物歧化酶（SOD-1）进行相对定量分析。通过使用血红蛋白凝胶去除血红蛋白，然后进行乙醇和氯仿萃取，从红细胞中制备SOD-1样品。糖化蛋白相对百分比测量的重现性良好，每次测量的标准偏差为4.0%。通过对几种比例的市售SOD-1和体外部分糖化SOD-1混合物进行质谱分析，发现游离和糖化的SOD-1具有相同的电离效率。对包括糖尿病患者在内的30名个体的SOD-1糖化百分比进行了测量。糖化水平范围为4.5%至低于检测限。从红细胞中提取的SOD-1样品通过Glyco-Gel B色谱法进行分离，分离出的组分通过质谱分析。吸附组分的质谱显示非糖化蛋白与Glyco-Gel B存在大量非特异性结合。
