Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
METABOLITE POOLS DURING STARCH SYNTHESIS AND CARBOHYDRATE OXIDATION IN AMYLOPLASTS ISOLATED FROM WHEAT ENDOSPERM
Autore:
TETLOW IJ; BLISSETT KJ; EMES MJ;
Indirizzi:
UNIV MANCHESTER,SCH BIOL SCI,3614 STOPFORD BLDG MANCHESTER M13 9PT LANCS ENGLAND UNIV MANCHESTER,SCH BIOL SCI MANCHESTER M13 9PT LANCS ENGLAND
Titolo Testata:
Planta
fascicolo: 1, volume: 204, anno: 1998,
pagine: 100 - 108
SICI:
0032-0935(1998)204:1<100:MPDSSA>2.0.ZU;2-0
Fonte:
ISI
Lingua:
ENG
Soggetto:
ADP-GLUCOSE PYROPHOSPHORYLASE; HEXOSE-PHOSPHATE TRANSLOCATOR; INORGANIC-PHOSPHATE; ENVELOPE MEMBRANES; SUSPENSION-CULTURES; SPINACH PROTOPLASTS; ROOT PLASTIDS; PHOSPHOGLUCOMUTASE; CHLOROPLASTS; TRANSPORT;
Keywords:
AMYLOPLAST; CARBOHYDRATE OXIDATION; STARCH SYNTHESIS; TRITICUM (AMYLOPLAST);
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
41
Recensione:
Indirizzi per estratti:
Citazione:
I.J. Tetlow et al., "METABOLITE POOLS DURING STARCH SYNTHESIS AND CARBOHYDRATE OXIDATION IN AMYLOPLASTS ISOLATED FROM WHEAT ENDOSPERM", Planta, 204(1), 1998, pp. 100-108

Abstract

Starch synthesis and CO2 evolution were determined after incubating intact and lysed wheat (Triticum aestivum L. cv. Axona) endosperm amyloplasts with C-14-labelled hexose-phosphates. Amyloplasts converted [U-C-14]glucose I-phosphate (Glc1P) but not [U-C-14]glucose 6-phosphate (Glc6P) into starch in the presence of ATP. When the oxidative pentose-phosphate pathway (OPPP) was stimulated, both [U-C-14]Glc1P and [U-C-14]Glc6P were metabolized to CO2, but Glc6P was the better precursor for the OPPP, and Glc1P-mediated starch synthesis was reduced by 75%. Inorder to understand the basis for the partitioning of carbon between the two potentially competing metabolic pathways, metabolite pools were measured in purified amyloplasts under conditions which promote bothstarch synthesis and carbohydrate oxidation via the OPPP. Amyloplastsincubated with Glc1P or Glc6P alone showed little or no interconversion of these hexose-phosphates inside the organelle. When amyloplasts were synthesizing starch, the stromal concentrations of Glc1P and ADP-glucose were high. By contrast, when flux through the OPPP was highest,Glc1P and ADP-glucose inside the organelle were undetectable, and there was an increase in metabolites involved in carbohydrate oxidation. Measurements of the plastidial hexose-monophosphate pool during starchsynthesis and carbohydrate oxidation indicate that the phosphoglucoseisomerase reaction is at equilibrium whereas the reaction catalysed by phosphoglucomutase is significantly displaced from equilibrium.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 01/04/20 alle ore 11:01:30