An amino acid a, isolated from the acid-catalyzed hydrolysis of a peptide antibiotic, gave a positive ninhydrin test and had a specific optical rotation (hcl solution) of 37.5 ml/(g·dm). compound a was not identical to any of the 20 essential amino acids. the isoelectric point of compound a was found to be 9.4. compound a can be prepared by the reaction of l-glutamine with br2 in naoh followed by acidification. suggest a structure for a.