title: Plant aminoaldehyde dehydrogenases oxidize a wide range of nitrogenous heterocyclic aldehydes.
abstract: The metabolic degradation of aldehydes is catalyzed by oxidoreductases from which aldehyde dehydrogenases (EC 1.2.1) comprise nonspecific or substrate-specific enzymes. The latter subset is represented, e.g., by NAD(+)-dependent aminoaldehyde dehydrogenases (AMADHs; EC 1.2.1.19) oxidizing a group of naturally occurring ω-aminoaldehydes including polyamine oxidation products. Recombinant isoenzymes from pea (PsAMADH1 and 2) and tomato (LeAMADH1 and 2) were subjected to kinetic measurements with synthetic aldehydes containing a nitrogenous heterocycle such as pyridinecarbaldehydes and their halogenated derivatives, (pyridinylmethylamino)-aldehydes, pyridinyl propanals and aldehydes derived from purine, 7-deazapurine and pyrimidine to characterize their substrate specificity and significance of the resulting data for in vivo reactions. The enzymatic production of the corresponding carboxylic acids was analyzed by liquid chromatography coupled to electrospray ionization mass spectrometry. Although the studied AMADHs are largely homologous and supposed to have a very similar active site architecture, significant differences were observed. LeAMADH1 displayed the broadest specificity oxidizing almost all compounds followed by PsAMADH2 and 1. In contrast, LeAMADH2 accepted only a few compounds as substrates. Pyridinyl propanals were converted by all isoenzymes, usually better than pyridinecarbaldehydes and aldehydes with fused rings. The K                         (m) values for the best substrates were in the range of 10(-5)-10(-4) M. Nevertheless, the catalytic efficiency values (V                         (max)/K                         (m)) reached only a very small fraction of that with 3-aminopropanal (except for LeAMADH1 activity with two pyridine-derived compounds). Docking experiments using the crystal structure of PsAMADH2 were involved to discuss differences in results with position isomers or alkyl chain homologs.
authors.affiliation: Department of Protein Biochemistry and Proteomics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 11, Olomouc, Czech Republic.
authors.forename: Jan
authors.initials: J
authors.lastname: Frömmel
authors.forename: Miroslav
authors.initials: M
authors.lastname: Soural
authors.forename: Martina
authors.initials: M
authors.lastname: Tylichová
authors.forename: David
authors.initials: D
authors.lastname: Kopečný
authors.forename: Gabriel
authors.initials: G
authors.lastname: Demo
authors.forename: Michaela
authors.initials: M
authors.lastname: Wimmerová
authors.forename: Marek
authors.initials: M
authors.lastname: Sebela
mesh_terms: D000445:Aldehyde Oxidoreductases / Q000737:chemistry*; D000447:Aldehydes / Q000737:chemistry*; D020816:Amino Acid Motifs; D020134:Catalytic Domain; D003198:Computer Simulation; D006571:Heterocyclic Compounds / Q000737:chemistry*; D007700:Kinetics; D018551:Solanum lycopersicum / Q000201:enzymology*; D008958:Models, Molecular; D018532:Pisum sativum / Q000201:enzymology*; D010940:Plant Proteins / Q000737:chemistry*; D011485:Protein Binding; D011994:Recombinant Proteins / Q000737:chemistry; D013379:Substrate Specificity
chemical_list: D000447:Aldehydes; D006571:Heterocyclic Compounds; D010940:Plant Proteins; D011994:Recombinant Proteins; D000445:Aldehyde Oxidoreductases; C019679:aminobutyraldehyde dehydrogenase