Aldehyde dehydrogenases (ALDHs) represent a superfamily of enzymes, which oxidize aldehydes to the corresponding acids. Certain families, namely ALDH9 and ALDH10, are best active with ω-aminoaldehydes arising from the metabolism of polyamines such as 3-aminopropionaldehyde and 4-aminobutyraldehyde. Plant ALDH10s show broad specificity and accept many different aldehydes (aliphatic, aromatic and heterocyclic) as substrates. This work involved the above-mentioned aminoaldehydes acylated with dicarboxylic acids, phenylalanine, and tyrosine. The resulting products were then examined with native ALDH10 from pea and recombinant ALDH7s from pea and maize. This investigation aimed to find a common efficient substrate for the two plant ALDH families. One of the best natural substrates of ALDH7s is aminoadipic semialdehyde carrying a carboxylic group opposite the aldehyde group. The substrate properties of the new compounds were demonstrated by mass spectrometry of the reaction mixtures, spectrophotometric assays and molecular docking. The N-carboxyacyl derivatives were good substrates of pea ALDH10 but were only weakly oxidized by the two plant ALDH7s. The N-phenylalanyl and N-tyrosyl derivatives of 3-aminopropionaldehyde were good substrates of pea and maize ALDH7. Particularly the former compound was converted very efficiently (based on the kcat/Km ratio), but it was only weakly oxidized by pea ALDH10. Although no compound exhibited the same level of substrate properties for both ALDH families, we show that these enzymes may possess more common substrates than expected.

• Keywords
• Acylation, Aldehyde dehydrogenase, Aminoaldehyde, Docking, Enzyme, Substrate,
• MeSH
• Aldehyde Dehydrogenase * metabolism   chemistry   genetics   MeSH
• Aldehydes * metabolism   chemistry   MeSH
• Pisum sativum * enzymology   MeSH
• Kinetics MeSH
• Zea mays * enzymology   MeSH
• Oxidation-Reduction MeSH
• Plant Proteins metabolism   chemistry   genetics   MeSH
• Molecular Docking Simulation * MeSH
• Substrate Specificity MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Aldehyde Dehydrogenase * MeSH
• Aldehydes * MeSH
• Plant Proteins MeSH

Polyamines participate in the processes of cell growth and development. The degradation branch of their metabolism involves amine oxidases. The oxidation of spermine, spermidine and putrescine releases hydrogen peroxide and the corresponding aminoaldehyde. Polyamine-derived aminoaldehydes have been found to be cytotoxic, and they represent the subject of this review. 3-aminopropanal disrupts the lysosomal membrane and triggers apoptosis or necrosis in the damaged cells. It is implicated in the pathogenesis of cerebral ischemia. Furthermore, 3-aminopropanal yields acrolein through the elimination of ammonia. This reactive aldehyde is also generated by the decomposition of aminoaldehydes produced in the reaction of serum amine oxidase with spermidine or spermine. In addition, acrolein is a common environmental pollutant. It causes covalent modifications of proteins, including carbonylation, the production of Michael-type adducts and cross-linking, and it has been associated with inflammation-related diseases. APAL and acrolein are detoxified by aldehyde dehydrogenases and other mechanisms. High-performance liquid chromatography, immunochemistry and mass spectrometry have been largely used to analyze the presence of polyamine-derived aminoaldehydes and protein modifications elicited by their effect. However, the main and still open challenge is to find clues for discovering clear linkages between aldehyde-induced modifications of specific proteins and the development of various diseases.

• Keywords
• 3-aminopropanal, Michael adduct, Schiff base, acrolein, aldehyde dehydrogenase, amine oxidase, aminoaldehyde, cytotoxicity, glutathione, protein modification,
• MeSH
• Acrolein * pharmacology   MeSH
• Aldehydes pharmacology   MeSH
• Polyamines * MeSH
• Spermidine pharmacology   MeSH
• Spermine pharmacology   MeSH
• Publication type
• Journal Article MeSH
• Review MeSH
• Names of Substances
• 3-aminopropionaldehyde MeSH Browser
• Acrolein * MeSH
• Aldehydes MeSH
• Polyamines * MeSH
• Spermidine MeSH
• Spermine MeSH

Aldehyde dehydrogenases (ALDHs) constitute a superfamily of NAD(P)+-dependent enzymes, which detoxify aldehydes produced in various metabolic pathways to the corresponding carboxylic acids. Among the 19 human ALDHs, the cytosolic ALDH9A1 has so far never been fully enzymatically characterized and its structure is still unknown. Here, we report complete molecular and kinetic properties of human ALDH9A1 as well as three crystal forms at 2.3, 2.9, and 2.5 Å resolution. We show that ALDH9A1 exhibits wide substrate specificity to aminoaldehydes, aliphatic and aromatic aldehydes with a clear preference for γ-trimethylaminobutyraldehyde (TMABAL). The structure of ALDH9A1 reveals that the enzyme assembles as a tetramer. Each ALDH monomer displays a typical ALDHs fold composed of an oligomerization domain, a coenzyme domain, a catalytic domain, and an inter-domain linker highly conserved in amino-acid sequence and folding. Nonetheless, structural comparison reveals a position and a fold of the inter-domain linker of ALDH9A1 never observed in any other ALDH so far. This unique difference is not compatible with the presence of a bound substrate and a large conformational rearrangement of the linker up to 30 Å has to occur to allow the access of the substrate channel. Moreover, the αβE region consisting of an α-helix and a β-strand of the coenzyme domain at the dimer interface are disordered, likely due to the loss of interactions with the inter-domain linker, which leads to incomplete β-nicotinamide adenine dinucleotide (NAD+) binding pocket.

• Keywords
• 3-aminopropionaldehyde, 4-trimethylaminobutyraldehyde, Homo sapiens, X‐ray crystallography, aldehyde dehydrogenase, structure-function,
• MeSH
• Aldehyde Dehydrogenase antagonists & inhibitors   chemistry   genetics   ultrastructure   MeSH
• Catalytic Domain genetics   MeSH
• Kinetics MeSH
• Protein Conformation * MeSH
• Crystallography, X-Ray MeSH
• Humans MeSH
• NAD genetics   MeSH
• Protein Structure, Secondary MeSH
• Amino Acid Sequence genetics   MeSH
• Substrate Specificity genetics   MeSH
• Binding Sites genetics   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Aldehyde Dehydrogenase MeSH
• ALDH9A1 protein, human MeSH Browser
• NAD MeSH

Almost 25 years ago, an enzyme named zeatin cis-trans isomerase from common bean has been described by Bassil et al. (1993). The partially purified enzyme required an external addition of FAD and dithiothreitol for the conversion of cis-zeatin to its trans- isomer that occurred only under light. Although an existence of this important enzyme involved in the metabolism of plant hormones cytokinins was generally accepted by plant biologists, the corresponding protein and encoding gene have not been identified to date. Based on the original paper, we purified and identified an enzyme from maize, which shows the described zeatin cis-trans isomerase activity. The enzyme belongs to nucleotide pyrophosphatase/phosphodiesterase family, which is well characterized in mammals, but less known in plants. Further experiments with the recombinant maize enzyme obtained from yeast expression system showed that rather than the catalytic activity of the enzyme itself, a non-enzymatic flavin induced photoisomerization is responsible for the observed zeatin cis-trans interconversion in vitro. An overexpression of the maize nucleotide pyrophosphatase/phosphodiesterase gene led to decreased FAD and increased FMN and riboflavin contents in transgenic Arabidopsis plants. However, neither contents nor the ratio of zeatin isomers was altered suggesting that the enzyme is unlikely to catalyze the interconversion of zeatin isomers in vivo. Using enhanced expression of a homologous gene, functional nucleotide pyrophosphatase/phosphodiesterase was also identified in rice.

• Keywords
• flavins, isomerization, maize, nucleotide pyrophosphatase/phosphodiesterase, zeatin,
• Publication type
• Journal Article MeSH

Plant ALDH10 family members are aminoaldehyde dehydrogenases (AMADHs), which oxidize ω-aminoaldehydes to the corresponding acids. They have been linked to polyamine catabolism, osmoprotection, secondary metabolism (fragrance), and carnitine biosynthesis. Plants commonly contain two AMADH isoenzymes. We previously studied the substrate specificity of two AMADH isoforms from peas (PsAMADHs). Here, two isoenzymes from tomato (Solanum lycopersicum), SlAMADHs, and three AMADHs from maize (Zea mays), ZmAMADHs, were kinetically investigated to obtain further clues to the catalytic mechanism and the substrate specificity. We also solved the high resolution crystal structures of SlAMADH1 and ZmAMADH1a because these enzymes stand out from the others regarding their activity. From the structural and kinetic analysis, we can state that five residues at positions 163, 288, 289, 444, and 454 (PsAMADHs numbering) can, directly or not, significantly modulate AMADH substrate specificity. In the SlAMADH1 structure, a PEG aldehyde derived from the precipitant forms a thiohemiacetal intermediate, never observed so far. Its absence in the SlAMADH1-E260A structure suggests that Glu-260 can activate the catalytic cysteine as a nucleophile. We show that the five AMADHs studied here are capable of oxidizing 3-dimethylsulfoniopropionaldehyde to the cryo- and osmoprotectant 3-dimethylsulfoniopropionate. For the first time, we also show that 3-acetamidopropionaldehyde, the third aminoaldehyde besides 3-aminopropionaldehyde and 4-aminobutyraldehyde, is generally oxidized by AMADHs, meaning that these enzymes are unique in metabolizing and detoxifying aldehyde products of polyamine degradation to nontoxic amino acids. Finally, gene expression profiles in maize indicate that AMADHs might be important for controlling ω-aminoaldehyde levels during early stages of the seed development.

• MeSH
• Aldehyde Oxidoreductases chemistry   genetics   metabolism   MeSH
• Aldehydes chemistry   MeSH
• Models, Chemical MeSH
• Phylogeny MeSH
• Plant Physiological Phenomena MeSH
• Kinetics MeSH
• Crystallography, X-Ray methods   MeSH
• Zea mays enzymology   MeSH
• Mutagenesis, Site-Directed MeSH
• NAD chemistry   MeSH
• Polyethylene Glycols chemistry   MeSH
• Gene Expression Regulation, Enzymologic * MeSH
• Gene Expression Regulation, Plant * MeSH
• Plants enzymology   MeSH
• Seeds metabolism   MeSH
• Solanum lycopersicum enzymology   MeSH
• Substrate Specificity MeSH
• Protein Binding MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Aldehyde Oxidoreductases MeSH
• Aldehydes MeSH
• NAD MeSH
• Polyethylene Glycols MeSH

Aminoaldehydes are products of polyamine degradation and are known to be reactive metabolites that are toxic to living cells at high concentrations. These compounds are catabolized by aminoaldehyde dehydrogenases, which are enzymes that contain a nicotinamide adenine dinucleotide coenzyme. Aminoaldehyde dehydrogenase from Pisum sativum was overexpressed in Escherichia coli, purified and crystallized using the hanging-drop method. A complete data set was collected to 2.8 A resolution at 100 K. Crystals belong to the monoclinic space group P2(1), with unit-cell parameters a = 86.4, b = 216.6, c = 205.4 A, beta = 98.1 degrees. Molecular replacement was performed and led to the identification of six dimers per asymmetric unit.

• MeSH
• Aldehyde Dehydrogenase chemistry   isolation & purification   metabolism   MeSH
• DNA Primers MeSH
• Electrophoresis, Polyacrylamide Gel MeSH
• Pisum sativum enzymology   MeSH
• Cloning, Molecular MeSH
• Protein Conformation MeSH
• Crystallization MeSH
• Crystallography, X-Ray MeSH
• Recombinant Proteins chemistry   isolation & purification   metabolism   MeSH
• Base Sequence MeSH
• Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization MeSH
• Blotting, Western MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Aldehyde Dehydrogenase MeSH
• DNA Primers MeSH
• Recombinant Proteins MeSH