AbstractIn this paper we report the preparation of specifically2H‐labelled L‐glutamic acids and2H‐,15N‐,13C‐labelled L‐glutamines on the gram scale. The products obtained have high isotope enrichment (>98%) and high optical purity. The synthetic schemes allow the specific isotope enrichment of every H, C, and N position or any combination of positions. (2‐2H)‐L‐Glutamic acid was synthesized by enantioselective enzymatic conversion of 2‐oxoglutaric acid using glutamate dehydrogenase (GDH, E.C. 1.4.1.3.), alcohol dehydrogenase (ADH, E.C. 1.1.1.1.) and (2H6)ethanol. (3,3‐2H2)‐L‐Glutamic acid was prepared by enzymatic conversion of 2‐oxo‐3,3‐di‐deuteroglutaric acid which was easily obtained from 2‐oxoglutaric acid by an isotope exchange reaction in2H2O at pH 13.0. (4,4‐2H2)‐L‐Glutamic acid was obtained by chemical exchange in 20%2HCl. Four different isotopomers of L‐glutamine [(2‐2H)‐, (3,3‐2H2)‐, (4,4‐2H2)‐, and (5‐13C)‐L‐Gln] were synthesized by the enantioselective conversion of isotopically labelled L‐glutamic acids using glutamine synthetase (GS, E.C. 6.3.1.2.). The amide group of glutamine was labelled with15N using15NH4Cl in the enzymatic reaction. The labelled L‐glutamic acids and L‐g