Toxic Amino Acids: Their Action as Antimetabolites

Fowden, L.; Lewis, D.; Tristram, H.

doi:10.1002/9780470122747.ch3

Cited by 89 publications

(38 citation statements)

References 209 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…T4C Survival Assay-T4C competes with Pro in the translation process (42,43) and can be degraded by Pro dehydrogenase in plants and bacteria (44,45). One-week-old WT and ProDH-OE tobacco seedlings (T 2 ) were transferred to MS medium containing 50 mM NaCl, 3 mM T4C, or 50 mM NaCl ϩ 3 mM T4C.…”

Section: Methodsmentioning

confidence: 99%

Unraveling Δ1-Pyrroline-5-Carboxylate-Proline Cycle in Plants by Uncoupled Expression of Proline Oxidation Enzymes

Miller

Honig

Stein

et al. 2009

Journal of Biological Chemistry

223

221

View full text Add to dashboard Cite

The two-step oxidation of proline in all eukaryotes is performed at the inner mitochondrial membrane by the consecutive action of proline dehydrogenase (ProDH) that produces ⌬ 1 -pyrroline-5-carboxylate (P5C) and P5C dehydrogenase (P5CDH) that oxidizes P5C to glutamate. This catabolic route is down-regulated in plants during osmotic stress, allowing free Pro accumulation. We show here that overexpression of MsProDH in tobacco and Arabidopsis or impairment of P5C oxidation in the Arabidopsis p5cdh mutant did not change the cellular Pro to P5C ratio under ambient and osmotic stress conditions, indicating that P5C excess was reduced to Pro in a mitochondrial-cytosolic cycle. This cycle, involving ProDH and P5C reductase, exists in animal cells and now demonstrated in plants. As a part of the cycle, Pro oxidation by the ProDH-FAD complex delivers electrons to the electron transport chain. Hyperactivity of the cycle, e.g. when an excess of exogenous L-Pro is provided, generates mitochondrial reactive oxygen species (ROS) by delivering electrons to O 2 , as demonstrated by the mitochondria-specific MitoSox staining of superoxide ions. Lack of P5CDH activity led to higher ROS production under dark and light conditions in the presence of Pro excess, as well as rendered plants hypersensitive to heat stress. Balancing mitochondrial ROS production during increased Pro oxidation is therefore critical for avoiding Pro-related toxic effects. Hence, normal oxidation of P5C to Glu by P5CDH is key to prevent P5C-Pro intensive cycling and avoid ROS production from electron run-off.Stress-related changes in Pro biosynthesis and degradation are conserved in different organisms and used to induce essential signaling pathways, such as p53-mediated apoptosis in mammalian cells (1) or osmo-protecting mechanisms in plants (2) and bacteria (3). Pro is one of the most common osmolytes that, together with glycine-betaine and soluble sugars, accumulates in plants in response to a wide array of abiotic and biotic stresses (2,4,5). Although the role of Pro as an osmo-protecting molecule in prokaryotes is well established (3, 6), the overall function of stress-accumulated free Pro in plants is still under debate (2, 7-9). In most plants, stress-induced free Pro accumulation results from enhanced Pro synthesis and concomitant silencing of Pro degradation (10 -13). Pro is produced in the cytosol and chloroplasts (14, 15) and degraded in the mitochondria by a short, strictly regulated cyclic pathway (Fig. 1). In the anabolic part of the pathway, glutamate is converted to ⌬ 1 -pyrroline-5-carboxylate (P5C) 3 by P5C synthetase (P5CS), and P5C-reductase (P5CR) reduces P5C to Pro. In an alternative pathway, P5C is generated from ornithine by mitochondrial ornithine-aminotransferase (16, 17) and is reduced to Pro by P5CR in the cytosol. Thus, a possible movement of P5C among organelles and cytosol is assumed. P5CS is considered the key enzyme in the synthesis route, and its expression is increased by osmotic stress in many plants (11, 16 -18). A singl...

show abstract

Section: Methodsmentioning

confidence: 99%

Unraveling Δ1-Pyrroline-5-Carboxylate-Proline Cycle in Plants by Uncoupled Expression of Proline Oxidation Enzymes

Miller

Honig

Stein

et al. 2009

Journal of Biological Chemistry

223

221

View full text Add to dashboard Cite

show abstract

“…13), which was discovered by Fowden (190) and independently by Virtanen (191) in young plants of Convalluriu mujulis (lily of the valley), and later in several other species such as Nicotzizna tabucum, Delonix regiu (Poinciana), and Beta species (sugar beets) (192)(193)(194)(195). The concentration in young lily-of-the-valley plants is particularly high; 20% or more of the ethanol-soluble nitrogen compounds is the azetidine-2-carboxylic acid fraction (196).…”

Section: Azetidine-2-carboxylic Acidmentioning

confidence: 96%

Methylthioadenosine

Schlenk

1983

Advances in Enzymology - And Related Areas of Molecular Biology

View full text Add to dashboard Cite

“…Existen otros aminoácidos de distribución restringida que son necesarios en procesos metabólicos básicos como la ornitina que es precursor en la síntesis de urea y la sarcopina que es intermediario en la síntesis de lisina. A diferencia de ornitina y sarcopina, la mayoría de los aminoácidos no protéicos aparentemente no tienen funciones reconocidas en procesos metabó-licos primarios sin embargo, algunas evidencias indican que los aminoácidos no protéicos son de gran importancia para asegurar la supervivencia de las especies (Fowden et al, 1967). A la fecha se conocen más de 240 amino ácidos no protéicos (ANP) aislados y caracterizados de plantas (Bell, 1980).…”

Section: Marcos Soto Hernández Et Alunclassified

Aminoácidos no proteicos en algunas especies de la subfamilia Mimosoideae con énfasis en el género Acacia sensu lato

2016

View full text Add to dashboard Cite

ResumenLos aminoácidos no protéicos de algunas especies en las tribus Acaciae, Ingeae y Mimoseae se investigaron por cromatografía de líquidos-espectrometría de masas a partir de extractos crudos de semillas y hojas. El análisis reveló compuestos característicos en los subgéneros Acacia, Aculeiferum y en el género Acaciella. Las semillas y hojas del subgénero Acacia se caracterizaron por la acumulación de ácido t-4-hidroxi pipecólico, ácido pipecólico, albizina (ácido-α-amino-β-ureido propiónico) y tres compuestos de naturaleza desconocida, mientras que en el caso de especies del subgénero Aculeiferum sus semillas y hojas acumularon ácido 2-amino-3-acetil propiónico, ácido 2-amino-4-acetil-amino butírico, ácido pipecólico y albizina. Ninguna de las especies analizadas del grupo de Acacia coulteri presentó ácido [β-(uracil-1-il-)α-amino propiónico](willardina). En las especies del género Acaciella los compuestos característicos fueron ácido 2-amino-3-acetil propiónico, ácido pipecólico y albizina. El estudio se completó comparando con algunas especies de la tribu Ingeae en la que el ácido 2-amino-3-acetil propiónico y el ácido 2-amino-4-acetil amino butírico fueron los aminoácidos más comunes. También se incluyeron y compararon algunas especies de la tribu Mimoseae, en la que los principales compuestos fueron el ácido t-4-hidroxi-pipecólico y el ácido pipecólico. Se discute la distribución de los compuestos detectados con estudios de otros tipos de caracteres y filogenias moleculares recientes y la propuesta de un esquema para el origen bioquímico que muestra una posible divergencia de especies. Palabras clave: Acacia, aminoácidos no proteicos, cromatografía líquida-espectrometría de masas. Nonproteic aminoacids in some species of the subfamily Mimosoideae with emphasis in the genus Acacia sensu lato AbstractNon protein amino acids of some species of the legume genera in the tribes Acaciae, Ingeae, and Mimoseae were surveyed by Liquid chromatography-mass spectrometry using crude extracts of seeds and leaves. This has revealed compounds characteristic of subgenera Acacia and Aculeiferum and the genus Acaciella. Seeds and leaves of Acacia subgenus were characterized by the accumulation of t-4-hydroxy-pipecolic acid, pipecolic acid, albizzine, and three unknown compounds, whereas compounds characteristic of seeds and leaves of subgenus Aculeiferum included 2-amino-3acetyl-propionic acid, 2-amino-4-acetyl amino butyric acid, t-4-hydroxy pipecolic acid, pipecolic acid and albizzine. None of the studied species of the Acacia coulteri group presented willardine. Characteristic compounds in the genus Acaciella were 2-amino-3-acetyl propionic acid, pipecolic acid and albizzine. The study was completed comparing with some species of the tribe Ingeae in which 2-amino-3-acetyl propionic acid and 2-amino-4-acetyl amino butyric acid were the more common compounds. Some species of the tribe Mimoseae were included and compared and their main compounds were t-4-hydroxy-pipecolic acid and pipecolic acid. The results are discussed ...

show abstract

Toxic Amino Acids: Their Action as Antimetabolites

Cited by 89 publications

References 209 publications

Unraveling Δ1-Pyrroline-5-Carboxylate-Proline Cycle in Plants by Uncoupled Expression of Proline Oxidation Enzymes

Unraveling Δ1-Pyrroline-5-Carboxylate-Proline Cycle in Plants by Uncoupled Expression of Proline Oxidation Enzymes

Methylthioadenosine

Aminoácidos no proteicos en algunas especies de la subfamilia Mimosoideae con énfasis en el género Acacia sensu lato

Contact Info

Product

Resources

About