A flavoenzyme containing non-covalently bound FAD. The enzyme from Bacillus subtilis is active with glycine, sarcosine, N-ethylglycine, D-alanine, D-α-aminobutyrate, D-proline, D-pipecolate and N-methyl-D-alanine. It differs from EC 1.4.3.3, D-amino-acid oxidase, due to its activity on sarcosine and D-pipecolate. The intermediate 2-iminoacetate is used directly by EC 2.8.1.10, thiazole synthase.