Kidney sialidase

Substrate specificity of the cytosolic sialidase from rat liver, kidney, and skeletal muscle is summarized in Table V. The enzyme from rat liver is active toward 4MU-Neu5Ac, sialyloligosaccharides, GM3, and, to a lesser degree, glycoprotein substrates. The enzyme preferentially hydrolyzes the a2-3-linked sialic acid residues as compared with the a2-6- and a2-8-linked residues. 

Substrates Rat liver Sialidase activity" Rat muscle s Rat kidneys... 

Other organs which have been reported to have sialidase activity are rat liver (Mahadevan et aL, 1967), rat and rabbit kidneys (Mahade-van et al., 1967 Kirschbaum and Bosmann, 1973 Kuratowska and Kubicka, 1967), ram testis (Roston et al., 1%6), human intestinal... 

Other compounds tested for their ability to inhibit or activate sialidase include iodoacetamide (10 m). AT-ethylmaleimide (10 m) and Mersalyl (10 m). On partially purified sialidase from pig kidney, these had no effect (Tuppy and Palese, 1968) a-chymotrypsin with sialidase from bovine brain caused an increase in activity (Gielen and Harprecht, 1969) EDTA, p-hydroxymercuribenzoate (formerly was believed to be p-chloromercuribenzoate), tested on sialidase in rat liver and kidney, had no effect (Mahadevan et al., 1967) the bacterial inhibitors 2-deoxy-2,3-dehydroneuraminic acid and p-nitrophenyloxamic acid tested on purified sialidase from rat heart muscle had no effect (Tallman and Brady, 1973) while l-(4-methoxyphenoxymethyl)-3,4-dehydroisoquino-line and p-hydroxymercuribenzoate were inhibitory with ganglioside Goia substrate. The effect of specific inhibitors on purified sialidase may give useful information about the active site, an unknown entity at this time. 

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