The chemical MeOSuc-Ala-Ala-Pro-Ala-chloromethylketone has a designated molecular formula of C20H31ClN4O7 and a molecular weight of 474.939 g/mol. Synonyms may include: Methoxysuccinyl-alanyl-alanyl-prolyl-alanine chloromethyl ketone, MSACK (ChemID).