Determination of l-Aspartic Acid by Aspartase.

Abstract

Three reactions-L-aspartic acidifumaric acid + NH3; fumaric acid + H2O malic acid; and L-aspartic acid + H2Omalic acid + NH3 -are probably concerned in the action on aspartic acid of aspartase prepns. which are not yet available free of fumarase and other enzymes. To determine equilibrium constants of the 1st reaction with aspartase, 3 parallel reactions and calculations are required: 1. enzyme soln. + buffer to detect NH3 formed from the prepn.; 2. enzyme soln. + buffer + known quantity of L-aspartic acid; and 3. enzyme soln. + buffer + unknown soln. Caseins with 15.7 and 14.6% N had 5.8 and 6.2% L-aspartic acid N. Enzyme prepns. were made from Pseudomonas fluorescens.