title: S-adenosyl-L-methionine decarboxylase of Acanthamoeba castellanii (Neff): purification and properties.
abstract: S-Adenosyl-L-methionine decarboxylase (AdoMetDC) has been purified to near homogeneity from the Neff strain of Acanthamoeba castellanii. The holoenzyme molecular mass is 88.8 kDa, including two copies each of a 32.8 kDa alpha-subunit and a 10-15 kDa beta-subunit. The alpha-subunit contains the active site. It has an N-terminal pyruvoyl group, and the first 19 amino acids are 63 and 74% identical with comparable sequences from yeast and mammals, respectively. The apparent Km for S-adenosylmethionine (AdoMet) in the presence of 2 mM putrescine was 30.0 microM. The enzyme was stimulated 2-fold by putrescine, but was unaffected by spermidine. It was inhibited by the following anti-metabolites, listed with their Ki values: Berenil (0.17 microM), pentamidine (19.4 microM), propamidine (334 microM), hydroxystilbamidine (357 microM), methylglyoxal bis(guanylhydrazone) (604 microM) and ethidium bromide (1.3 mM). Activity of the enzyme fell to undetectable levels during cell differentiation (encystment).
authors.affiliation: Department of Molecular Genetics, Ohio State University, Columbus 43210.
authors.forename: E R
authors.initials: ER
authors.lastname: Hugo
authors.forename: T J
authors.initials: TJ
authors.lastname: Byers
mesh_terms: D000048:Acanthamoeba / Q000201:enzymology* / Q000254:growth & development; D012437:Adenosylmethionine Decarboxylase / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D002455:Cell Division / Q000502:physiology; D004795:Enzyme Stability; D005839:Gentamicins / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007526:Isoelectric Point; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010419:Pentamidine / Q000031:analogs & derivatives; D011773:Pyruvates / Q000032:analysis; D017386:Sequence Homology, Amino Acid
chemical_list: D005839:Gentamicins; D011773:Pyruvates; D010419:Pentamidine; C010680:antibiotic G 418; D012437:Adenosylmethionine Decarboxylase