IMMOBILISED ENZYMES AND THEIR USE IN AMINOACID ELECTROSENSORS

摘要

07-21(542)A IMMOBILISED ENZYMES AND THEIR USE IN AMINOACID ELECTROSENSORS The enzymes L-methionine gamma lyase, L-lysine decarboxylase, aspartase and tryptophanase are immobilised by contacting the enzyme with a latex of polymer particles having a negative surface charge such that the electrophoretic mobility of the latex has a negative value of -2.0 10 8m2V 1sec 1 or below when measured at pH 7 in 0.01 M KNO3 and a polymer solids concentration of 30 mg/l, the polymer particles also having a hydrophobic surface such that the contact angle of a 1 microlitre droplet of distilled water with a plane horizontal surface formed by drying and compacting the latex particles is 70.degree. or more. The polymer-immobilised enzymes can be used for assaying the corresponding aminoacids in aqueous solutions using an electrosensor comprising a pHsensitive electrode (6) located in a sensing zone or chamber (1) containing the enzyme/polymer particles as an aqueous dispersion or in water-dispersible form.