SysPTM 2.0: an updated systematic resource for post-translational modification. - Jing Li; Jia Jia 002; Hong Li 013; Jian Yu; Han Sun; Ying He; Daqing Lv; Xiaojuan Yang; Michael O. Glocker; Liang-Xiao Ma; Jiabei Yang; Ling Li; et al. (Database J. Biol. Databases Curation, 2014)