Determination of L-tyrosine by enzyme catalytic spectrophotometry

A simple and sensitive spectrophotometric method for the determination of L-tyrosine was developed based on the inhibition of L-tyrosine on enzyme catalysis system.The optimal experimental conditions are studied.The concentration of L-tyrosine showed a good linear relationship with percentage inhibition of enzyme catalysis system when ranged between 5.0×10-7mol/L~1.0×10-4mol/L.The detection limit of L-tyrosine was 2.6×10-7mol/L.The relative standard deviation of 11 parallel determinations was 2.1% for 2.0×10-5mol/L L-tyrosine.This method was successfully applied to determine L-tyrosine in beer and grape wine.