Biochemical properties of a neuraminidase of Trichomonas vaginalis.
Trichomonas vaginalis possesses a membrane-associated neuraminidase activity that is released into culture medium during its growth in vitro. The neuraminidase shows an optimum pH of 4.5 and a Km of 0.15 mM for 2'-(4-methylumbelliferyl)-alpha-D-N-acetyl-neuraminic acid as a substrate. This enzyme releases mainly alpha-2,3-linked sialic acid because it is able to liberate sialic acid from sialyllactose (mainly alpha-2,3) but not from mucin (alpha-2,6) or fixed erythrocytes (mainly alpha-2,6). The neuraminidase activity is strongly inhibited by 2,3-dehydro-2-deoxy-N-acetyl neuraminic acid, whereas EGTA and Ca2+ do not affect the activity. Gel filtration-fast protein liquid chromatography of culture supernatant displays a single peak of neuraminidase activity with molecular weight 52,000. The levels of neuraminidase activity are variable in fresh and long-term grown isolates of T. vaginalis, regardless of time in culture. However, there are 2 kinds of isolates, 1 group with high neuraminidase activity and able to secrete the enzyme during growth and the other with low neuraminidase activity. The results suggest that T. vaginalis possesses a membrane-associated neuraminidase that is present to a variable degree in different isolates.
Padilla-Vaca
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Instituto de Investigación en Biología Experimental, Facultad de Química, Universidad de Guanajuato, México.
Anaya-Velázquez
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D000818:Animals; D003470:Culture Media / Q000032:analysis; D004789:Enzyme Activation; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D008970:Molecular Weight; D009439:Neuraminidase / Q000737:chemistry* / Q000378:metabolism; D013379:Substrate Specificity; D013997:Time Factors; D014247:Trichomonas Vaginitis / Q000097:blood / Q000201:enzymology / Q000469:parasitology; D014246:Trichomonas vaginalis / Q000201:enzymology* / Q000254:growth & development / Q000302:isolation & purification
D003470:Culture Media; D009439:Neuraminidase