毛细管电泳与MALDI-TOF/MS联用测定血清转甲状腺素蛋白的化学修饰

摘要

Objective To establish a combined method for analysis of serum transthyretin ( TTR) chemical modification using capillary electrophoresis ( CE) with matrix-assisted laser desorption ionization-time-of-flight mass spectrometry ( MALDI-TOF/MS) analysis. Methods Enzyme-linked immunosorbent assay ( ELISA) was used to determine serum TTR in 20 senile systemic amyloidosis ( SSA) patients and 20 healthy subjects. Serum TTR was separated by CE. Determination of TTR chemical modification was analyzed by MALDI-TOF/MS. Results The levels of serum TTR was (0. 25 ± 0. 04 ) g/L in control group and (0. 26 ± 0. 03 ) g/L in SSA patients, and there was no significant difference between control group and SSA patients (P > 0. 05). The chemical modification of TTR found 4 TTR chemical modification peaks, as native TTR [mass-to-charge ratio (m/z) : 13 750. 86 ± 1. 48] , sul-TTR ( m/z ratio: 13 830. 63 ±2. 76) , cys-TTR (m/z ratio; 13 871. 70 ±2. 70) and cysgly-TTR (m/z ratio; 13 919.00 + 14.77) by MALDI-TOF/MS analysis. Conclusions The combined method of CE with MALDI-TOF/MS analysis can be used directly to determine the chemical modification of TTR.%目的 建立一种毛细管电泳(CE)与基质辅助激光解吸/电离飞行时间质谱(MALDI-TOF/MS)联用测定血清转甲状腺素蛋白(TTR)化学修饰的方法.方法 用酶联免疫吸附法(ELISA)测定20例老年性淀粉样变( SSA)患者及20名健康体检者血清TTR浓度；CE法分离血清TTR并利用MALDI-TOF/MS测定TTR的化学修饰.结果 健康对照组及SSA组血清TTR浓度分别为0.25±0.04、(0.26 ±0.03) g/L,2组间差异无统计学意义(P＞ 0.05);MALDI-TOF/MS分析共发现4个TTR化学修饰峰,质/荷比(m/z)分别为:13 750.86±1.48、13 830.63±2.76、13 871.70 ±2.70、13 919.00±14.77；分别对应未修饰-TTR、磺化-TTR、半胱氨酸-TTR和半胱氨酸甘氨酸-TTR.结论 CE法分离血清TTR能够直接利用MALDI-TOF-MS测定其化学修饰,可用于临床检测血清TTR的化学修饰.