^ abStorer, R. James; Ferrante, Antonio (10 October 1997). "Radiochemical Assay of Diamine Oxidase". Polyamine Protocols. Methods in Molecular Biology. Vol. 79. New Jersey: Humana Press. pp. 91–96. doi:10.1385/0-89603-448-8:91. ISBN978-0-89603-448-8. PMID9463822. In biological mixtures γ-aminobutyraldehyde may be alternatively oxidized by aldehyde dehydrogenases (EC 1.2.1.3) to γ-aminobutyric acid (GABA) (11—13). The formation of 4-amino-1-butanol is also possible through reduction by aldehyde dehydrogenase and/or alcohol dehydrogenase (13,14), thus preventing cyclization. Other fates of putrescine in biological mixtures include the acetylation to acetylputrescine by an N-acetyltransferase and then oxidation by monoamine oxidase (EC 1.4.3.4) (11,17). [...] Fig 1 Fates of putrescine in biological mixtures
^Takahashi H, Uchikura K, Takahashi H (June 1961). "Relationship between pharmacological actions on the mammalian ileum and chemical structure of gamma-aminobutyric acid". Jpn J Physiol. 11 (3): 229–237. doi:10.2170/jjphysiol.11.229. PMID13774871.
^Takahashi H, Koshino C, Ikeda O (February 1962). "Relationship between the hypotensive activity and chemical structure of gamma-aminobutyric acid in the rabbit". Jpn J Physiol. 12: 97–105. doi:10.2170/jjphysiol.12.97. PMID13919036.
^ abRashmi, Deo; Zanan, Rahul; John, Sheeba; Khandagale, Kiran; Nadaf, Altafhusain (2018). "γ-Aminobutyric Acid (GABA): Biosynthesis, Role, Commercial Production, and Applications". Studies in Natural Products Chemistry. Vol. 57. Elsevier. pp. 413–452. doi:10.1016/b978-0-444-64057-4.00013-2. ISBN978-0-444-64057-4. Alternate pathways of GABA synthesis from putrescine and other polyamines have also been reported [207–211]. Here, γ-aminobutyraldehyde, an intermediate from polyamine degradation reaction via combined activities of diamine oxidase (DAO, E.C. 1.4.3.6) and 4-aminobutyraldehyde dehydrogenase (ABALDH), leads to the synthesis of GABA [205,212,213]. In response to abiotic stresses, GABA is also reported to be synthesized from proline via D1-pyrroline intermediate formation [47,205,214] and also by a nonenzymatic reaction [214]. However, GABA synthesis from polyamine pathways is minor in the brain, [215] although they play a significant role in the developing brain [216] and retina [217]. But GABA can be formed from putrescine in the mammalian brain [218].
^ abShelp BJ, Bozzo GG, Trobacher CP, Zarei A, Deyman KL, Brikis CJ (September 2012). "Hypothesis/review: contribution of putrescine to 4-aminobutyrate (GABA) production in response to abiotic stress". Plant Sci. 193–194: 130–135. Bibcode:2012PlnSc.193..130S. doi:10.1016/j.plantsci.2012.06.001. PMID22794926.
^ abBenedetti MS, Dostert P (1994). "Contribution of amine oxidases to the metabolism of xenobiotics". Drug Metab Rev. 26 (3): 507–535. doi:10.3109/03602539408998316. PMID7924902. MAO also catalyses the deamination of a natural brain constituent, monoacetyl-putrescine, producing y-acetylaminobutyraldehyde, which in turn participates in the formation of brain GABA [13].