title: Putrescine-activated S-adenosylmethionine decarboxylase from Acanthamoeba culbertsoni.
abstract: Acanthamoeba culbertsoni, the free living pathogenic amoeba responsible for fatal meningoencephalitis, contains an S-adenosylmethionine decarboxylase (EC 4.1.1.50) which is strongly activated by putrescine and to a lesser extent by cadaverine; spermidine, spermine, diaminopropane and 1,6-diaminohexane are inactive. Methylglyoxal bis-(guanylhydrazone) competitively inhibited the enzyme with a Ki value of 123 microM. The enzyme was strongly inhibited by berenil (Ki = 0.5 microM) and to a lesser extent by pentamidine. The putrescine-activated enzyme is inhibited by MgCl2. The apparent molecular weight of 110,000 and its enzymatic properties indicate that the enzyme has characteristics intermediate between the bacterial and eukaryotic S-adenosylmethionine decarboxylases.
mesh_terms: D012437:Adenosylmethionine Decarboxylase / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D000656:Amoeba / Q000201:enzymology*; D000818:Animals; D002262:Carboxy-Lyases / Q000378:metabolism*; D002474:Cell-Free System; D004133:Diminazene / Q000031:analogs & derivatives / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D007700:Kinetics; D008670:Metals / Q000494:pharmacology; D008935:Mitoguazone / Q000494:pharmacology; D008970:Molecular Weight; D010419:Pentamidine / Q000494:pharmacology; D011700:Putrescine / Q000494:pharmacology*
chemical_list: D008670:Metals; D010419:Pentamidine; D002262:Carboxy-Lyases; D012437:Adenosylmethionine Decarboxylase; C003915:diminazene aceturate; D008935:Mitoguazone; D011700:Putrescine; D004133:Diminazene