Exo-alpha-sialidase that catalyzes the hydrolytic cleavage of the terminal sialic acid (N-acetylneuraminic acid, Neu5Ac) of a glycan moiety in the catabolism of glycolipids, glycoproteins and oligosacharides. Recognizes sialyl linkage positions of the glycan moiety as well as the supramolecular organization of the sialoglycoconjugate. Displays preference for alpha-(2->3)-sialylated GD1a and GT1B gangliosides over alpha-(2->8)-sialylated GD1b, in both monomeric forms and micelles. Hydrolyzes monomeric GM1 ganglioside, but has no activity toward the miscellar form. Has lower sialidase activity for glycoproteins such as fetuin and TF/transferrin that carry a mixture of alpha-(2->3) and alpha-(2->6)-sialyl linkages. Cleaves milk oligosaccharide alpha-(2->3)-sialyllactose, but is inactive toward alpha-(2->6)-sialyllactose isomer. Has no activity toward colominic acid, a homomer of alpha-(2->8)-linked Neu5Ac residues. Hydrolysis of alpha-(2->3)-, alpha-(2->6)-, alpha-(2->8)- glycosidic linkages of terminal sialic acid residues in oligosaccharides, glycoproteins, glycolipids, colominic acid and synthetic substrates. ganglioside GD1a + H2O = ganglioside GM1 + N-acetylneuraminate ganglioside GM1 + H2O = ganglioside GA1 + N-acetylneuraminate ganglioside GT1b + H2O = ganglioside GD1b + N-acetylneuraminate ganglioside GD1b + H2O = ganglioside GM1 + N-acetylneuraminate ganglioside GD3 + H2O = ganglioside GM3 + N-acetylneuraminate ganglioside GM3 + H2O = beta-D-galactosyl-(1->4)-beta-D-glucosyl-(1<->1)-ceramide + N-acetylneuraminate ganglioside GM2 + H2O = N-acetyl-beta-D-galactosaminyl-(1->4)-beta-D-galactosyl-(1->4)-beta-D-glucosyl-(1<->1')-ceramide + N-acetylneuraminate a neolactoside IV(3)-alpha-NeuAc-nLc4Cer(d18:1(4E)) + H2O = a neolactoside nLc4Cer(d18:1(4E)) + N-acetylneuraminate H2O + N-acetyl-alpha-neuraminosyl-(2->3)-beta-D-galactosyl-(1->4)-D-glucose = lactose + N-acetylneuraminate Detected in skeletal muscle. Belongs to the glycosyl hydrolase 33 family.