"Catalyzes the oxidation 4-aminobutanal (gamma-aminobutyraldehyde) to 4-aminobutanoate (gamma-aminobutyrate or GABA). This is the second step in one of two pathways for putrescine degradation, where putrescine is converted into 4-aminobutanoate via 4-aminobutanal. Also functions as a 5-aminopentanal dehydrogenase in a a L-lysine degradation pathway to succinate that proceeds via cadaverine, glutarate and L-2-hydroxyglutarate."xsd:string