title: An immobilized bienzyme system for assay of sialic acid.
abstract: Sialic acid has been assayed enzymatically by an immobilized two-enzyme system. The method includes cleavage of sialic acid to pyruvic acid by N-acetylneuraminic acid (NANA) aldolase and reduction of pyruvic acid by lactate dehydrogenase in the presence of NADH, which is followed photometrically at 349 nm. For the membrane preparation 5 units of lactate dehydrogenase and 1 unit of NANA-aldolase were used. The pH optimum of the reaction using potassium phosphate buffer was 7.0. This two-enzyme membrane remains 100% active for several weeks at 4 degrees C in the assay buffer and remains stable after performing experiments at 45 degrees C.
mesh_terms: D000818:Animals; D002417:Cattle; D003016:Clostridium perfringens / Q000201:enzymology; D004800:Enzymes, Immobilized / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007770:L-Lactate Dehydrogenase / Q000378:metabolism*; D009206:Myocardium / Q000201:enzymology; D007652:Oxo-Acid-Lyases / Q000378:metabolism*; D012794:Sialic Acids / Q000032:analysis*; D013696:Temperature
chemical_list: D004800:Enzymes, Immobilized; D012794:Sialic Acids; D007770:L-Lactate Dehydrogenase; D007652:Oxo-Acid-Lyases; C018728:N-acetylneuraminate lyase