scholarly journals 3-Nitropropionic acid oxidase from horseshoe vetch (Hippocrepis comosa): a novel plant enzyme

1999 ◽  
Vol 340 (2) ◽  
pp. 491-495 ◽  
Author(s):  
Charles R. HIPKIN ◽  
Mansour A. SALEM ◽  
Deborah SIMPSON ◽  
Stephen J. WAINWRIGHT
Keyword(s):  
Enzyme Activity ◽  
Acid Oxidase ◽  
Leaf Extracts ◽  
Nitropropionic Acid ◽  
A Subunit ◽  
High Concentrations ◽  
Nitrate And Nitrite ◽  
Plant Enzyme ◽  
3 Nitropropionic Acid

A novel enzyme that catalyses the oxygen-dependent oxidation of 3-nitropropionic acid (3NPA) to malonate semialdehyde, nitrate, nitrite and H2O2 has been purified from leaf extracts of the horseshoe vetch, Hippocrepis comosa, and named 3NPA oxidase. The enzyme is a flavoprotein with a subunit molecular mass of 36 kDa containing 1 molecule of FMN and exhibits little specificity for all nitroalkanes tested other than 3NPA (apparent Km 620 μM). The maximum enzyme activity in vitro was expressed at pH 4.8 and was inhibited strongly by the products nitrate and nitrite. 3NPA oxidase activity was detected in green shoots, which also contain high concentrations of 3NPA, from plants grown with nitrate, ammonium or N2 as sources of nitrogen. Enzyme activity was absent from roots and cell cultures, neither of which accumulate high levels of 3NPA.

scholarly journals 3-Nitropropionic acid oxidase from horseshoe vetch (Hippocrepis comosa): a novel plant enzyme

1999 ◽  
Vol 340 (2) ◽  
pp. 491 ◽  
Author(s):  
Charles R. HIPKIN ◽  
Mansour A. SALEM ◽  
Deborah SIMPSON ◽  
Stephen J. WAINWRIGHT
Keyword(s):  
Acid Oxidase ◽  
Nitropropionic Acid ◽  
Plant Enzyme ◽  
3 Nitropropionic Acid

scholarly journals Regioselectivity of glucosylation of caffeic acid by a UDP-glucose:glucosyltransferase is maintained in planta1

2003 ◽  
Vol 373 (3) ◽  
pp. 987-992 ◽  
Author(s):  
Eng-Kiat LIM ◽  
Gillian S. HIGGINS ◽  
Yi LI ◽  
Dianna J. BOWLES
Keyword(s):  
Enzyme Activity ◽  
Caffeic Acid ◽  
Northern Blot Analysis ◽  
Transgenic Arabidopsis ◽  
Structural Features ◽  
Cauliflower Mosaic Virus ◽  
Leaf Extracts ◽  
Transgenic Lines ◽  
First Time

Caffeic acid is a phenylpropanoid playing an important role in the pathways leading to lignin synthesis and the production of a wide variety of secondary metabolites. The compound is also an antioxidant and has potential utility as a general protectant against free radicals. Three glucosylated forms of caffeic acid are known to exist: the 3-O- and 4-O-glucosides and the glucose ester. This study describes for the first time a glucosyltransferase [UDP-glucose:glucosyltransferase (UGT)] that is specific for the 3-hydroxyl, and not the 4-hydroxyl, position of caffeic acid. The UGT sequence of Arabidopsis, UGT71C1, has been expressed as a recombinant fusion protein in Escherichia coli, purified and assayed against a range of substrates in vitro. The assay confirmed that caffeic acid as the preferred substrate when compared with other hydroxycinnamates, although UGT71C1 also exhibited substantial activity towards flavonoid substrates, known to have structural features that can be recognized by many different UGTs. The expression of UGT71C1 in transgenic Arabidopsis was driven by the constitutive cauliflower mosaic virus 35 S (CaMV35S) promoter. Nine independent transgenic lines were taken to homozygosity and characterized by Northern-blot analysis, assay of enzyme activity in leaf extracts and HPLC analysis of the glucosides. The level of expression of UGT71C1 was enhanced considerably in several lines, leading to a higher level of the corresponding enzyme activity and a higher level of caffeoyl-3-O-glucoside. The data are discussed in the context of the utility of UGTs for natural product biotransformations.

Memantine reduces neuronal dysfunctions triggered by in vitro ischemia and 3-nitropropionic acid

2007 ◽  
Vol 207 (2) ◽  
pp. 218-226 ◽  
Author(s):  
A. Tozzi ◽  
C. Costa ◽  
M. Di Filippo ◽  
M. Tantucci ◽  
S. Siliquini ◽  
...  
Keyword(s):  
In Vitro Ischemia ◽  
Nitropropionic Acid ◽  
3 Nitropropionic Acid

Properties of Na, K-ATPase from the salivary glands of the ixodid tick Amblyomma hebraeum

1980 ◽  
Vol 58 (6) ◽  
pp. 1052-1059 ◽  
Author(s):  
B. Rutti ◽  
B. Schlunegger ◽  
W. Kaufman ◽  
A. Aeschlimann
Keyword(s):  
Enzyme Activity ◽  
Salivary Glands ◽  
Fluid Secretion ◽  
Ixodid Tick ◽  
Rich Source ◽  
Amblyomma Hebraeum ◽  
Fundamental Properties ◽  
High Concentrations

Tick (Amblyomma hebraeum) salivary glands are a rich source of Na,K-ATPase (EC 3.6.1.3), the fundamental properties of which are similar to those of Na,K-ATPases from other sources. Inhibition of the enzyme by ouabain is quantitatively similar to the inhibition of fluid secretion by this drug. Harmaline at high concentrations also inhibited the Na,K-ATPase. The nucleotides GTP, ITP, and UTP were utilized as substrates, but all were less effective than ATP. Noradrenaline, dopamine, and phenoxybenzamine, all at concentrations known to influence fluid secretion in vitro, had no effect on enzyme activity.

scholarly journals Orphenadrine prevents 3-nitropropionic acid-induced neurotoxicity in vitro and in vivo

2001 ◽  
Vol 132 (3) ◽  
pp. 693-702 ◽  
Author(s):  
David Pubill ◽  
Ester Verdaguer ◽  
Anna Ma Canudas ◽  
Francesc Xavier Sureda ◽  
Elena Escubedo ◽  
...  
Keyword(s):  
Nitropropionic Acid ◽  
3 Nitropropionic Acid
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