Neuraminidase from Arthrobacter nicotianae,eas purified by chromatography on DEAE-cellulose, gel-filtration on Sephadex G-150, and chromatography on CM-cellulose. The molecular, mass of the highly purified neuraminidase was found to be approximately 69 kDa by SDS-PAGE. The pH anti temperature optima were 5.0 and 45 degrees C, respectively. The enzyme was stable at temperatures up to 50 degrees C, Ca2+, Ba2+, and Mg2+ activated the enzyme, but Pb2+, Fe3+, and the chelating agent EDTA were inhibitory. The purified neuraminidase had a K-m value of 3.17 mM when glucomacropeptide was the substrate.