(L-Cys-gly)-nem 99127-64-7 Glycine, N-(S-(1-ethyl-2,5-dihydro-2,5-dioxo-1H-pyrrol-3-yl)-L-cysteinyl)- N-Ethylmaleimide-cysteinyl-glycine S-(Ethylsuccinimido)-L-cysteinyl-glycine