Evidence for a tonoplast-associated form of sucrose synthase and its potential involvement in sucrose mobilization from the vacuole

The following work presents new evidence for a tonoplast localization of sucrose synthase and its functional role during the mobilization of vacuolar sucrose. Highly purified tonoplast vesicles were associated with significant SuSy levels as determined by immuno-recognition, enzymatic activity, and...

Ausführliche Beschreibung

Bibliographische Detailangaben
Veröffentlicht in:Journal of experimental botany. - 1985. - 54(2003), 386 vom: 27. Mai, Seite 1407-14
1. Verfasser: Etxeberria, Ed (VerfasserIn)
Weitere Verfasser: Gonzalez, Pedro
Format: Aufsatz
Sprache:English
Veröffentlicht: 2003
Zugriff auf das übergeordnete Werk:Journal of experimental botany
Schlagworte:Journal Article Research Support, Non-U.S. Gov't Carbon Radioisotopes Membrane Proteins Plant Proteins Sucrose 57-50-1 Glucosyltransferases EC 2.4.1.- sucrose synthase mehr... EC 2.4.1.13 Uridine Diphosphate Glucose V50K1D7P4Y
Beschreibung
Zusammenfassung:The following work presents new evidence for a tonoplast localization of sucrose synthase and its functional role during the mobilization of vacuolar sucrose. Highly purified tonoplast vesicles were associated with significant SuSy levels as determined by immuno-recognition, enzymatic activity, and by-product measurements. Total tonoplast-bound SuSy was estimated to be approximately 7% of the total tissue activity. SuSy affinity to the tonoplast was confirmed by the lack of SuSy displacement by ionic washes and also by the tonoplast ability to bind to exogenously added SuSy as compared to the cytosolic marker alcohol dehydrogenase. UL-[(14)C]sucrose-loaded vesicles incubated with ATP and UDP produced [(14)C]UDP-Glc as determined by UDP-Glc dehydrogenase and by the ability of the product to bind to DEAE-cellulose and to co-migrate with authentic UDP-Glc on TLC. ATP alone induced sucrose efflux but not the production of [(14)C]ADP-Glc. Kinetic analysis of [(14)C]UDPG formation under conditions of low sucrose availability suggests sucrose channelling between the ATP-dependent sucrose transporter and SuSy, thus corroborating the association of SuSy with the tonoplast and its involvement in sucrose mobilization from the vacuole
Beschreibung:Date Completed 25.07.2003
Date Revised 13.05.2019
published: Print
Citation Status MEDLINE
ISSN:1460-2431