QUANTITATION OF GLYCEROPHOSPHORYLCHOLINE BY FLOW-INJECTION ANALYSIS USING IMMOBILIZED ENZYMES

A method for quantitating glycerophosphorylcholine by flow injection a nalysis is reported in the present paper. Glycerophosphorylcholine pho sphodiesterase and choline oxidase, immobilized on controlled porosity glass beads, are packed in a small reactor inserted in a flow injecti on manifold. When samples containing glycerophosphorylcholine are inje cted, glycerophosphorylcholine is hydrolyzed into choline and sn-glyce rol-3-phosphate. The free choline produced in this reaction is oxidize d to betain and hydrogen peroxide. Hydrogen peroxide is detected amper ometrically. Quantitation of glycerophosphorylcholine in samples conta ining choline and phosphorylcholine is obtained inserting ahead of the reactor a small column packed with a mixed bed ion exchange resin. Th e time needed for each determination does not exceed one minute. Quant itation of glycerophosphorylcholine in samples containing choline and phosphorylcholine is obtained inserting ahead of the reactor a small c olumn packed with a mixed bed ion exchange resin. The time needed for each determination does not exceed one minute. The present method, app lied to quantitate glycerophosphorylcholine in samples of seminal plas ma, gave results comparable with those obtained using the standard enz ymatic-spectrophotometric procedure. An alternative procedure, making use of co-immobilized glycerophosphorylcholine phosphodiesterase and g lycerol-3-phosphate oxidase for quantitating glycerophosphorylcholine, glycerophosphorylethanolamine and glycerophosphorylserine is also des cribed.