Monitoring of Tyrosine during Proteolysis of Oyster Extract by Flow Injection System with Immobilized Enzyme Reactor

Abstract

A flow injection analytical system for the determination of L-tyrosine was developed. The system included an immobilized enzyme reactor, in which L-tyrosinase was immobilized on controlled pore glass supports. The system was applied to the L-tyrosine determination in oyster extracts which were treated with proteolytic enzyme. Oxygen consumption involved in L-tyrosinase enzyme reaction was monitored. The carrier solution used was 0.1M phosphate buffer (pH 7.2). The detection limit was 0.01mM, and the range for determination was 0.1-1.0mM. The relative standard deviakion was 1.9% for 10 successive determinations at 0.5mM level. When the system was applied to the determination of L-tyrosine in oyster extracts, the results were in good agreement witht hose obtained by the HPLC method. The system appeared to be useful for monitoring of L-tyrosine in oysker exkract treaked with proteolytic enzyme.