@article{mbs:/content/journal/micro/10.1099/00221287-146-10-2715, author = "Yarlett, Nigel and Martinez, Martha P. and Goldberg, Burt and Kramer, Debora L. and Porter, Carl W.", title = "Dependence of Trichomonas vaginalis upon polyamine backconversion", journal= "Microbiology", year = "2000", volume = "146", number = "10", pages = "2715-2722", doi = "https://doi.org/10.1099/00221287-146-10-2715", url = "https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-146-10-2715", publisher = "Microbiology Society", issn = "1465-2080", type = "Journal Article", keywords = "DENSpm, di(ethyl)norspermine", keywords = "Trichomonas", keywords = "SSAT, spermidine:spermine N1-acetyltransferase", keywords = "polyamine oxidation", keywords = "acetylated polyamines", keywords = "Polyamines", keywords = "ODC, ornithine decarboxylase", abstract = " Trichomonas vaginalis grown for 16 h in the presence of [14C]spermine formed a high intracellular pool of [14C]spermidine and a small but detectable pool of [14C]putrescine. When [3H]putrescine was added to the growth medium, a large intracellular pool of [3H]putrescine was found, but it was not further metabolized, confirming previous studies suggesting the absence of a forward-directed polyamine synthetic pathway in T. vaginalis. Spermidine:spermineN 1-acetyltransferase (SSAT) and polyamine oxidase enzyme activities were detected which collectively converted spermine to spermidine. Polyamine oxidase was localized in the hydrogenosome-enriched fraction, whereas SSAT was found predominantly in the cytosolic fraction. In the presence of saturating substrate, the trichomonad SSAT had an activity of 0·39±0·09 nmol min−1 (mg protein)−1 (the mean of five analyses) and an apparent K m for spermine of 1·7 μM. The enzyme was competitively inhibited by di(ethyl)norspermine with a K i of 28 μM. Growth studies indicated that 50 μM di(ethyl)norspermine caused a 68% and 84% reduction in the intracellular concentrations of spermidine and spermine, respectively. The trichomonad polyamine oxidase required FAD as a cofactor and had an apparent K m of 6·0 μM forN 1-acetylspermine. The potential of bis(alkyl) polyamine analogues as antitrichomonad agents is discussed.", }