Mitochondrial delta-1-pyrroline-5-carboxylate dehydrogenase (ALDH4A1) catalyzes the reaction of 4-hydroxy-L-glutamate gamma-semialdehyde and NAD+ to form 4-hydroxyglutamate and NADH + H+. ALDH4A1 also catalyzes the corresponding reaction of proline catabolism, as shown in biochemical and structural studies (Adams & Goldstone 1960; Srivastava et al. 2012), and mutations in ALDH4A1 disrupt both catabolic processes in human patients (Valle et al. 1979).
1-pyrroline-5-carboxylate dehydrogenase activity of ALDH4A1 dimer [mitochondrial matrix]