Specificity studies on the oligosaccharide neuraminidase of human fibroblasts.

Competition and thermal inactivation experiments with different potential natural substrates indicated that in homogenates of human fibroblasts one single enzyme is acting on both (alpha 2-3) and (alpha 2-6) sialosyl linkages of oligosaccharides and glycoproteins, but not of the ganglioside GM3. N-Acetylneuraminic and 2-deoxy-2,3-dehydro-N-acetylneuraminic acids are competitive inhibitors, whereas chondroitin 4-sulphate and the drug Suramin are potent inhibitors of undefined type.