Continuous assay of neuraminidase activity by a bienzyme system immobilized in an artificial membrane

Abstract

Lactate dehydrogenase and NANA‐lyase were immobilized in an artificial gelantine membrane. This bienzyme system was used for continuous assay of neuraminidase activity. The K′_m of the active membrane for lactate dehydrogenase and NANA‐lyase using NADH, pyruvic acid, and N‐acetylneuraminic acid as substrates were found to be 0.25mM, 0.75mM, and 2.1mM, respectively. The K_m of soluble neuraminidase using sialyllactose as substrate was found to be 0.13 mM. The pH optimum for neuraminidase activity was 6.0. At 45°C the reaction rate was higher, and no denaturation phenomena of the immobolized enzymes have been observed. This bienzyme membrane was stable for several weeks stored in the reaction buffer at 4°C.