Enables succinate-semialdehyde dehydrogenase (NAD+) activity. Predicted to be involved in gamma-aminobutyric acid catabolic process. Predicted to be active in mitochondrion. Is expressed in adult head and adult heart. Human ortholog(s) of this gene implicated in succinic semialdehyde dehydrogenase deficiency. Orthologous to human ALDH5A1 (aldehyde dehydrogenase 5 family member A1).