Identification of the Ndh (NAD(P)H-Plastoquinone-oxidoreductase) Complex in Etioplast Membranes of Barley: Changes during Photomorphogenesis of Chloroplasts

2000 ◽  
Vol 41 (1) ◽  
pp. 49-59 ◽  
Author(s):  
A. Guera ◽  
P. G. de Nova ◽  
B. Sabater
Keyword(s):  
Etioplast Membranes

Optical Multichannel Analysis of Protochlorophyllide Phototransformation in Detergent-Solubilized Etioplast Membranes of Wheat

1994 ◽  
Vol 49 (1-2) ◽  
pp. 125-131 ◽  
Author(s):  
Fabrice Franck ◽  
Mohammed Aziz Ouazzani ◽  
Esther Dujardin ◽  
Radovan Popovic
Keyword(s):  
Continuous Light ◽  
Multichannel Analysis ◽  
Triton X ◽  
Kinetics Of ◽  
Etioplast Membranes ◽  
Protochlorophyllide Phototransformation ◽  
Absorbance Spectra

Extracts of wheat etioplast membranes obtained after treatment with 7 mᴍ n-octyl-β-ᴅ-glucopyranoside (OG), n-dodecyl-β-ᴅ-maltoside (DM) or Triton X-100 contained the three spectral forms of Pchlide (the photoactive Pchlide638 and Pchlide650 and the inactive Pchlide630) in various relative amounts . The OG extract had a Pchlide composition close to that of the intact membranes whereas the DM extract was enriched in Pchlide638 and the Triton extract was enriched in Pchlide630. Measurements of the kinetics of phototransformation and of timeresolved absorbance spectra during phototransformation in continuous light shows that the inactive Pchlide630 is in fact slowly transformed to Chlide, especially in the Triton extract where this form is more abundant. Addition of NADPH favours the phototransformation of Pchlide630 and the slow regeneration of Pchlide638 and Pchlide650 from Pchlide630 in darkness after illumination. No such regeneration was however observed in the Triton extract. NADPH had only slight effects on the Chlide shift towards shorter wavelengths after phototransformation in solubilized membranes.

scholarly journals Purification of the enzyme NADPH: protochlorophyllide oxidoreductase

1981 ◽  
Vol 195 (1) ◽  
pp. 83-92 ◽  
Author(s):  
N S Beer ◽  
W T Griffiths
Keyword(s):  
Specific Activity ◽  
Gradient Centrifugation ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
High Specific Activity ◽  
Sucrose Density Gradient ◽  
Sucrose Density Gradient Centrifugation ◽  
Triton X ◽  
Etioplast Membranes

A procedure for the purification of the enzyme NADPH:protochlorophyllide oxidoreductase is described. This involves fractionation of sonicated oat etioplast membranes by discontinuous-sucrose-density-gradient centrifugation, which gives membranes in which the enzyme is present at a high specific activity. The enzyme is solubilized from the membranes with Triton X-100, followed by gel filtration of the extract; enzyme activity is eluted in fractions corresponding to a mol.wt of approx. 35000. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis of the enzyme-containing fractions from gel filtration shows two peptides, of mol.wts. approx. 35000 and 37000.

scholarly journals Substrate-specificity studies on protochlorophyllide reductase in barley (Hordeum vulgare) etioplast membranes

1980 ◽  
Vol 186 (1) ◽  
pp. 267-278 ◽  
Author(s):  
W T Griffiths
Keyword(s):  
Carboxylic Acid ◽  
Methyl Ester ◽  
Hordeum Vulgare ◽  
Substrate Specificity ◽  
Acid Group ◽  
Carboxylic Acid Group ◽  
Naturally Occurring ◽  
Protochlorophyllide Reductase ◽  
Nickel Copper ◽  
Etioplast Membranes

1. The substrate specificity of the enzyme protochlorophyllide reductase in barley (Hordeum vulgare) etioplasts was investigated. 2. It was shown that naturally occurring esterified protochlorophyllide and chemically prepared protochlorophyllide methyl ester are not substrates for the enzyme, suggesting an important role for the C-7 carboxylic acid group in binding of the porphyrin to the enzyme. 3. Removal of magnesium from the protochlorophyllide leads to inactivity of the compound as a substrate for the enzyme. However, activity can be restored by replacing the magnesium with zinc, whereas nickel, copper or cobalt failed to restore substrate activity. 4. Binding of the second substrate, NADPH, to the enzyme probably occurs through the 2'-phosphate group in the coenzyme.

Sunflower etioplast membranes

1979 ◽  
Vol 68 (3) ◽  
pp. 325-327 ◽  
Author(s):  
Nicoletta Rascio ◽  
Giorgio Casadoro
Keyword(s):  
Etioplast Membranes

scholarly journals Identification of Etioplast Membranes in Fractions from Soybean Hypocotyls

1979 ◽  
Vol 64 (3) ◽  
pp. 398-403 ◽  
Author(s):  
William J. Hurkman ◽  
D. James Morré ◽  
Charles E. Bracker ◽  
Hilton H. Mollenhauer
Keyword(s):  
Etioplast Membranes

scholarly journals Covalent labelling of the NADPH: protochlorophyllide oxidoreductase from etioplast membranes with [3H]N-phenylmaleimide

1981 ◽  
Vol 195 (1) ◽  
pp. 93-101 ◽  
Author(s):  
R P Oliver ◽  
W T Griffiths
Keyword(s):  
Hordeum Vulgare ◽  
Avena Sativa ◽  
Ternary Complex ◽  
Thiol Groups ◽  
Protochlorophyllide Oxidoreductase ◽  
Protochlorophyllide Reductase ◽  
Enzyme Substrates ◽  
Specific Manner ◽  
Etioplast Membranes ◽  
Single Peptide

[3H]N-Phenylmaleimide has been used to covalently label in a specific manner the substrate-protected thiol groups of the enzyme protochlorophyllide reductase. In membrane preparations from oat (Avena sativa) and runner-bean (Phaseolus vulgaris) seedlings, two related peptides of mol.wts. 35000/37000 and 34000/35000 respectively and showing properties expected of the reductase have been identified, whereas the same technique with barley (Hordeum vulgare) extracts resulted in labelling a single peptide of mol.wt. 38000. Evidence is presented that both NADPH and protochlorophyllide are required for protection of the essential thiol groups on the reductase in oat extracts, a situation favouring a ternary complex as the structure for the photoactive enzyme--substrates intermediate.

scholarly journals Light-harvesting Chlorophylla/b-binding Protein Stably Inserts into Etioplast Membranes Supplemented with Zn-pheophytina/b

1997 ◽  
Vol 272 (33) ◽  
pp. 20451-20455 ◽  
Author(s):  
Andrea Kuttkat ◽  
Ingrid Edhofer ◽  
Lutz A. Eichacker ◽  
Harald Paulsen
Keyword(s):  
Light Harvesting ◽  
Binding Protein ◽  
Etioplast Membranes
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