Abstract
Overlaps of glutamine and asparagine with threonine in aminogram were proved when the samples prepared by the Stein and Moore's procedure were analyzed with Technicon amino acid analyzer by means of gradient elution technique.
A simple procedure was developed to remove these acid amides. Biological samples for amino acid assay, prepared by routine procedure, were dissolved in citrate buffer (pH 2.2) and heated at 120°C for 15 minutes. This procedure results in the conversion of asparagine into aspartic acid and of glutamine into ninhydrin-negative pyrrolidone carboxylic acid. The heated samples are could be served for analysis without any further treatment. Precautions have to be taken to keep the strict heating conditions, otherwise glutamic acid in samples also converts into pyroglutamic acid.
