Selectively catalyzes the oxidative deamination of acidic amino acids (PubMed:1991137, PubMed:20603179, PubMed:23391306, PubMed:25747990, PubMed:28393897, PubMed:28560262, PubMed:28629864, PubMed:29292239, PubMed:31914658, PubMed:32553892, PubMed:9163533). Suppresses the level of D-aspartate in the brain, an amino acid that can act as an agonist for glutamate receptors (PubMed:28560262). Protects the organism from the toxicity of D-amino acids (By similarity). May also function in the intestine (By similarity). {ECO:0000250|UniProtKB:D3ZDM7, ECO:0000250|UniProtKB:Q922Z0, ECO:0000269|PubMed:1991137, ECO:0000269|PubMed:20603179, ECO:0000269|PubMed:23391306, ECO:0000269|PubMed:25747990, ECO:0000269|PubMed:28393897, ECO:0000269|PubMed:28560262, ECO:0000269|PubMed:28629864, ECO:0000269|PubMed:29292239, ECO:0000269|PubMed:31914658, ECO:0000269|PubMed:32553892, ECO:0000269|PubMed:9163533}. This is the function of DDO (D-aspartate oxidase, ENSG00000203797).