CATALYTIC PROPERTIES OF NEURAMINIDASE FROM NONCHOLERAIC VIBRIOS

Main catalytic properties of commercially available neuraminidase preparations from noncholeraic vibrios were studied. The enzymatic activity was measured using a simple resorcinol procedure. Optimal conditions for neuraminidase effect: pH 5.5-6.0 and buffer composition, were characterized. Affinity of the enzyme to various substrates was studied using 10 natural and synthetic sialoconjugates. K(m) values were studied for fetuin, ovomucin and transferrin used as optimal substrates. When influence of metal ions, detergents, complexones and other compounds was studied, activation of neuraminidase was found in presence of bivalent metal ions, especially of Ca2+, while chelate-formating complexones and heavy metal salts inhibited the enzyme. These results may be used in studies of the neuraminidase action mechanism and regulation of its activity.