A Colorimetric Procedure for the Determination of Aspartic Acid.

Abstract
A procedure is described for the detn. of aspartic acid in quantities of 0.5 mg. or above in the sample. The amino acid is converted to fumaric acid by treatment with dimethyl sulfate. The fumaric acid precipitated as the Cu-pyridyl complex and the Cu thus combined is determined colorimetrically, employing Na diethyldithiocarbamate. Recoveries from synthetic mixtures and a casein hydrolysate are reported. The aspartate of crystalline lysozyme is 10.60% and that of crystalline bovine serum albumin is 9.92% when assayed by this procedure.