Document Detail


NAD turnover and utilisation of metabolites for RNA synthesis in a reaction sensing the redox state of the cytochrome b6f complex in isolated chloroplasts.
MedLine Citation:
PMID:  7505745     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
NAD is normally regarded as a redox molecule or as the substrate for ADP-ribosylation reactions. In this study, we describe the rapid metabolism of NAD by Percoll-gradient-purified lettuce chloroplasts and show that the adenine moiety can be incorporated into RNA in a dark-activated reaction that senses the redox state of the cytochrome b6f complex. Isolated chloroplasts rapidly metabolised radiolabelled NAD+ to 5'-AMP (within seconds) and adenosine during a 60-min incubation in vitro; the products were analysed by high-performance liquid chromatography. No radiolabelled ADP-ribose was detected. Radioactivity was incorporated into trichloroacetic-acid-insoluble material during this period, with approximately 2-4-fold more incorporation occurring in the dark. Most of this radiolabel was rendered acid-soluble by dilute alkaline digestion at 37 degrees C, yielding an approximately equal mixture of 2'-AMP and 3'-AMP, and by RNase digestion, identifying the acid-insoluble radioactive material as RNA. Protein-bound ADP-ribose would have yielded 5'-AMP and/or oligomeric/polymeric ADP-ribose after alkali digestion. The utilisation of NAD metabolites for RNA synthesis was restricted to the thylakoid compartment of the chloroplast. The use of a variety of electron-transport inhibitors such as 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone, bromanil (tetrabromo-1,4-benzoquinone), electron donors (dithiothreitol), electron acceptors (ferricyanide) and an uncoupler showed that the incorporation of radiolabel from NAD into acid-insoluble material was favoured when the cytochrome b6f complex was in the oxidised state (as pertaining to incubations in the dark).
Authors:
C K Pearson; S B Wilson; R Schaffer; A W Ross
Related Documents :
11282575 - Ascorbic acid changes the pattern of purine metabolism during germination of white spru...
11232205 - A historical perspective on the discovery of adenyl purines.
18380775 - Twenty-three novel alleles increase diversity at the hla-c locus.
851535 - Synthesis of polynucleotides which contain 3,n4-ethanocytidine, a nucleoside modificati...
20503935 - Hplc and tlc enantioseparation of the nitro-positioned aryloxysubstituted aminopropanols.
25311565 - Herg blocking potential of acids and zwitterions characterized by three thresholds for ...
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  European journal of biochemistry / FEBS     Volume:  218     ISSN:  0014-2956     ISO Abbreviation:  Eur. J. Biochem.     Publication Date:  1993 Dec 
Date Detail:
Created Date:  1994-02-03     Completed Date:  1994-02-03     Revised Date:  2007-07-23    
Medline Journal Info:
Nlm Unique ID:  0107600     Medline TA:  Eur J Biochem     Country:  GERMANY    
Other Details:
Languages:  eng     Pagination:  397-404     Citation Subset:  IM    
Affiliation:
Department of Molecular and Cell Biology, University of Aberdeen, Scotland.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Chloroplasts / enzymology*
Chromatography, High Pressure Liquid
Cytochromes / chemistry,  metabolism*
Cytochromes f
Electron Transport / drug effects
Hydrogen-Ion Concentration
Kinetics
Light
NAD / metabolism*
Oxidation-Reduction
RNA / biosynthesis*
Radioisotopes
Chemical
Reg. No./Substance:
0/Cytochromes; 0/Radioisotopes; 53-84-9/NAD; 63231-63-0/RNA; 9035-46-5/Cytochromes f

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


Previous Document:  Isolation and characterization of the human inter-alpha-trypsin inhibitor heavy-chain H1 gene.
Next Document:  Expression of beta 1, beta 3, beta 4, and beta 5 integrins by human lung carcinoma cells of differen...