Process for preparing D-2-amino-2,3-dimethylbutyramide and/or L-2-amino-2,3-dimethylbutyric acid, wherein an aqueous solution of DL-2-amino-2,3-dimethylbutyramide is contacted with a preparation containing an aminoacyl amidase which has been obtained from a culture of Mycobacterium neoaurum and in that subsequently D-2-amino-2,3-dimethyl- butyramide and/or L-2-amino-2,3-dimethyl-butyric acid is (are) recovered from the resulting hydrolysis mixture. The compound D-2-amino-2,3-dimethylbutyramide is novel.