PURIFICATION, CRYSTALLIZATION, AND CHARACTERIZATION OF NEURAMINIDASE FROM MICROMONOSPORA-VIRIDIFACIENS

Neuraminidase was purified from the culture filtrate of Micromonospora viridifaciens in 4 steps. After the last step the enzyme appeared to be homogeneous on polyacrylamide gel electrophoresis, and the enzyme was crystallized by the addition of ammonium sulfate. The enzyme did not require Ca2+ ions for the activity and was not inhibited by EDTA. The enzyme was active on various sialocompounds such as N-acetylneuraminosyl-lactose (Km = 2.1 mM) and colominic acid (Km = 0.3 mM). The activity was strongly inhibited by a sulfhydryl reagent, p-chloromercuribenzoate, and by oxidizing reagents such as N-bromosuccinimide and iodine. Its catalytic properties were compared with those of various microbial neuraminidases. M. viridifaciens neuraminidase was similar in many respects to Clostridium perfringens enzyme.