Plants amine oxidases

Welford R. W. D. Lam A. Mirica L. M. Klinman J. P. Partial conversion of Hansenula polymorpha amine oxidase into a plant amine oxidase implications for copper chemistry and mechanism. Biochemistry 2007, 46, 10817-10827. 

Plant amine oxidase from Euphorbia characias is not sensitive to hydrogen peroxide in the absence of substrate [128]. In the presence of substrate and in absence of catalase, however, either hydrogen peroxide formed by the reaction or more rapidly the hydrogen peroxide added before initiating the enzymatic reaction causes total inactivation. The inactivation is considered to be related to the sulfhydryl group... 

Alcazar R, AltabeUa T, Marco F et al (2010) Polyamines molecules with regulatory functions in plant abiotic stress tolerance. Planta (Berl) 231 1237-1249 Angelini R, Bragaloni M, Federico R et al (1993) Involvement of polyamines, diamine oxidase and peroxidase in resistance of chickpea to Ascochyta rabiei. J Plant Physiol 142 704-709 AngeUni R, Federico R, Bonfante P (1995) Maize polyamine oxidase antibody production and ultra structural localization. J Plant Physiol 146 686-692 AngeUni R, Cona A, Federico R et al (2010) Plant amine oxidases on the move an update. Plant Physiol Biochem 48 560-564... 

In most terrestrial plant-pathogen interactions a diphenylene-iodonium (DPI)-sensitive (O Donnell et al. 1993), membrane-located, and receptor-activated NADPH oxidase generates superoxide radicals (Levine et al. 1994 Doke and Miura 1995 Lamb and Dixon 1997 Bolwell et al. 1998), which eventually dis-mutate into H202 and 02 (Sutherland 1991). Apoplastic peroxidases (Bolwell et al. 1998 Martinez et al. 1998), as well as various oxidases such as oxalate oxidase (Zhang et al. 1995 Thordal-Christensen et al. 1997) or amine oxidase (Laurenzi et al. 2001 Rea et al. 2002), have also been identified as sources of ROS in higher plants. 

Rea G, Metoui O, Infantino A, Federico R, Angelini R (2002) Copper amine oxidase expression in defense responses to wounding and Ascochyta rabiei invasion. Plant Physiol 128 865-875 Roeder V, Collen J, Rousvoal S, Corre E, Leblanc C, Boyen C (2005) Identification of stress gene transcripts in Laminaria digitata (Phaeophyceae) protoplast cultures by Expressed Sequence Tag analysis. J Phycol 41 1227-1235... 

Dennis J. McKenna, G. H. N. Towers, and F. S. Abbott. "Mono-amine oxidase inhibitors in South American hallucinogenic plants Tryptamine and B-carboline constituents of Ayahuasca". Journal of Ethnopharmacology 10 (1984) 195-223. 

The ayahuasca potion is made of two plants, one of which reassembles double-helical vines. Ayahuasca contains the psychoactive chemicals DMT and several harmaline alkaloids. DMT can be extracted and smoked with powerful effect. However, eating DMT does little because MAO (mono-amine oxidase) in our guts deactivates the DMT when DMT is taken orally. On the other hand, the alkaloids in ayahuasca inhibit MAO in the gut, so that the brew is psychoactive. I wonder how the indigenous peoples of the Amazon ever figured out what plants from the thousands of plants in the forest to combine to get both the DMT and the MAO-inhibitor. 

The same cofactor is present in an amine oxidase from E. co/z457-460 and in other bacterial461-463 fungal,463a plant,464 and mammalian4643 amine oxidases. 

A fourth possibility is the generation of H202 via oxidation of putrescine (butane-1,4-diamine 2.56). This reaction is catalyzed by copper amine oxidase (E.C. 1.4.3.6). Copper amine oxidases are homodimers in which each unit contains a copper ion and a 1,3,5-trihydroxyphenylalanine quinine co-factor. In plants copper amine oxidases generally oxidize putrescine to 4-aminobutanal (2.57). This latter compound undergoes spontaneous cyclization to A1 pyrroline (2.58), ammonia, and H202, as shown in Figure 2-12 (Medda et al., 1995). 

In plants, aliphatic di- and polyamines have been implicated in many processes including rapid cell division, fruit development, stress response and senescence (Evans and Malmberg, 1989 Galston and Kaur-Sawhney, 1995). Amine oxidases catalyse the eatabolism of biogenic amines and hence could be involved in regulating sueh eellular processes. It is eonve-nient to separate discussion of the roles of the copper-containing idiamine... 

It is safe to predict that there will be major effort in understanding the biological roles of copper-containing amine oxidases and the relationship to flavin-containing amine oxidases. The diversity of amine oxidases in all forms of life and their involvement in key cellular processes in plants and mammals underline the importance of this objective. 

Medda, R., Padiglia, A., and Floris, G., 1995, Plant copper amine oxidases. Phytochemistry 39 ln9. 

Smith, T. A., 1985, The di- and poly-amine oxidases of higher plants, Biochem. Soc. Trans., 13 319n322. 

Copper plays an important role in the constituents of many enzymes of the mammalian organism as well as in plants and anthropods. Several classes of oxidizing enzymes for copper have been described, including the cytochrome oxidases which are the terminal oxidases in the mitochondrial electron transport system, a key reaction in energy metabolism (34), and the amine oxidases (35) of which there are a number that contain copper (36,37,38), Lysyl oxidase (39) is probably the most important since it plays a major role in elastin and collagen synthesis... 

There is evidence that both these routes can occur. The enzymes converting tryptophan to indoleacetic acid can be obtained in maize embryo juice the tryptophan is thought to arise from the endosperm (964). Indolepyruvic acid is also present in maize endosperm (837, 838), suggesting it to be an intermediate. On the other hand, tryptamine is converted to indoleacetic acid in plants (304, 815) and the amine oxidase responsible has been studied by Kenten and Mann (464). Consideration of the biogenesis of alkaloids, discussed later, suggests that both tryptamine and indoleacetaldehyde are likely to occur in plants. 

Amine oxidase occurs in all types of organisms, from prokaryotes to animals and plants. While its catalytic function is understood, its physiological function remains unknown. Various functions have been suggested [114] ... 

Structure of the active center. The active centers of this dimeric enzyme are so well embedded into its protein structure that they are inaccessible to the solvent. The two centers are situated approximately 30 A apart from each other but connected by /3-strands. The active center consists of a type 2 copper center and a cofactor. Sequence comparisons have established that the residues His 8, His 246, and His 357 coordinate the copper ions in both yeast and plants (e.g., lentil seeds) [120,122]. The participating cofactor is typical for amine oxidases, diamine oxidases, and lysyl oxidases but has not yet been found in any other protein - 2,4,5-trihydroxy-phenylalanine quinone [123, 124] (also known as TOPA-quinone, TPQ or 6-hydroxy-DOPA quinone), an internal cofactor which is created by post-translational modification of the tyrosine in position 387 [120]. The consensus sequence of the amino acids neighboring the TOPA cofactor are conserved in all known amine oxidases - Asn-TOPA-Asp/Glu [113,120, 123,125-127]. The positions of the histidine ligands relative to TOPA quinone are conserved in all known amine oxidases as well. The chain lengths of the amine oxidase monomers vary according to the organism of origin 692 residues in yeast [128], 762 in bovine serum amine oxidase [128,129] and 569 in the enzyme from lentil seeds [120,130]. 

Diamine oxidase occurs, like amine oxidase, in bacteria, animals, and plants [133]. The comparison of amino acid sequences of the amiloride-binding protein from human kidney, rat colon, diamine oxidase from human placenta, pig kidney, and amine oxidase from Hansenula polymorpha and lentil seeds has shown that the amiloride-binding protein and diamine oxidase are identical proteins[29]. The amiloride-binding protein was previously postulated to function as an epithelial sodium-transporter. While its physiological function is still... 

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