CHARACTERIZATION OF GLUCOSE-6-PHOSPHATE INCORPORATION INTO STARCH BY ISOLATED INTACT CAULIFLOWER-BUD PLASTIDS

Autor(en): NEUHAUS, HE
HENRICHS, G
SCHEIBE, R 
Stichwörter: ADENYLATE TRANSLOCATOR; ADP-GLUCOSE; AMYLOPLASTS; BIOSYNTHESIS; CHENOPODIUM-RUBRUM; ENZYMIC CAPACITIES; INNER MEMBRANE; INORGANIC-PHOSPHATE; Plant Sciences; SOLANUM-TUBEROSUM; TRIOSE PHOSPHATES
Erscheinungsdatum: 1993
Herausgeber: OXFORD UNIV PRESS INC
Journal: PLANT PHYSIOLOGY
Volumen: 101
Ausgabe: 2
Startseite: 573
Seitenende: 578
Zusammenfassung: 
Intact plastids from cauliflower (Brassica oleracea var Prince de Bretagne) buds were isolated according to the method described by Journet and Douce (E.P. Journet and R. Douce [1985] Plant Physiol 79: 458-467). Incubation of these plastids with various C-14-labeled compounds revealed that glucose-6-phosphate can act as a precursor f or starch synthesis. However, significant rates (incorporation of 120 nmol glucose mg-1 protein h-1) could only be observed when both 3-phosphoglyceric acid and ATP were present as well. Starch synthesis in isolated plastids was strongly dependent upon the intactness of the organelle. The presence of a high-affinity ATP/ADP translocator with a K(m) for ATP of 12 mum was demonstrated by uptake experiments with [C-14]ATP. ADP inhibited both ATP uptake and effector-stimulated starch synthesis. Effector-stimulated glucose-6-phosphate-dependent starch synthesis was not significantly influenced by fructose-6-phosphate or 2-deoxyglucose-6-phosphate but was strongly inhibited by triose phosphate and inorganic phosphate. Starch synthesis was also inhibited by 4,4'-diisothio-cyanostilbene-2,2'-disulfonate, which is known to be a potent inhibitor of the chloroplast phosphate translocator. The data presented here support the view that starch biosynthesis in heterotrophic tissues is powered by increasing levels of cytosolic 3-phosphoglyceric acid and ATP when glucose-6-phosphate is available.
ISSN: 00320889
DOI: 10.1104/pp.101.2.573

Show full item record

Page view(s)

2
Last Week
0
Last month
1
checked on Feb 23, 2024

Google ScholarTM

Check

Altmetric