Converts gamma-trimethylaminobutyraldehyde into gamma-butyrobetaine with high efficiency (in vitro). Can catalyze the irreversible oxidation of a broad range of aldehydes to the corresponding acids in an NAD-dependent reaction, but with low efficiency. 4-(trimethylamino)butanal + H2O + NAD(+) = 4-(trimethylamino)butanoate + 2 H(+) + NADH an aldehyde + H2O + NAD(+) = a carboxylate + 2 H(+) + NADH Amine and polyamine biosynthesis; carnitine biosynthesis. Homotetramer. Belongs to the aldehyde dehydrogenase family.