Mass Spectrometric Analysis of Proteoforms of Cyclophilin A from Human Colorectal Carcinoma Tissues / 分析化学

ABSTRACT

Cyclophilin A was isolated from human colorectal carcinoma tissues by ultrafiltration,affinity chromatography,and two dimensional electrophoresis.By the aid of Western blot analysis,several isoforms of cyclophilin A were detected.,The tryptic digests from cyclophilin A were analyzed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry as well as electrospray tandem mass spectrometry techniques.Several different modifications such as N-terminal acetylation (Ac-1Met and Ac-2Val) and phosphorylation of 5Thr were identified from these isoforms of cyclophilin A,which represented the majority of the proteoforms of cyclophilin A in this study.In addition,other kinds of modifications such as oxidation and deamidation were also found in these proteoforms.The results indicated that the developed method could be used to rapidly and correctly identify the several proteoforms of cyclophilin A isolated from human colorectal carcinoma tissues.