Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

A transglucosidase necessary for starch degradation and maltose metabolism in leaves at night acts on cytosolic heteroglycans (SHG)

A transglucosidase necessary for starch degradation and maltose metabolism in leaves at night... The recently characterized cytosolic transglucosidase DPE2 (EC 2.4.1.25) is essential for the cytosolic metabolism of maltose, an intermediate on the pathway by which starch is converted to sucrose at night. In in vitro assays, the enzyme utilizes glycogen as a glucosyl acceptor but the in vivo acceptor molecules remained unknown. In this communication we present evidence that DPE2 acts on the recently identified cytosolic water‐soluble heteroglycans (SHG) as does the cytosolic phosphorylase (EC 2.4.1.1) isoform. By using in vitro two‐step 14C labeling assays we demonstrate that the two transferases can utilize the same acceptor sites of the SHG. Cytosolic heteroglycans from a DPE2‐deficient Arabidopsis mutant were characterized. Compared with the wild type the glucose content of the heteroglycans was increased. Most of the additional glucosyl residues were found in the outer chains of SHG that are released by an endo‐α‐arabinanase (EC 3.2.1.99). Additional starch‐related mutants were characterized for further analysis of the increased glucosyl content. Based on these data, the cytosolic metabolism of starch‐derived carbohydrates is discussed. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Plant Journal Wiley

A transglucosidase necessary for starch degradation and maltose metabolism in leaves at night acts on cytosolic heteroglycans (SHG)

Loading next page...
 
/lp/wiley/a-transglucosidase-necessary-for-starch-degradation-and-maltose-YDYCnZjtSJ

References (33)

Publisher
Wiley
Copyright
Copyright © 2006 Wiley Subscription Services, Inc., A Wiley Company
ISSN
0960-7412
eISSN
1365-313X
DOI
10.1111/j.1365-313X.2006.02732.x
pmid
16640603
Publisher site
See Article on Publisher Site

Abstract

The recently characterized cytosolic transglucosidase DPE2 (EC 2.4.1.25) is essential for the cytosolic metabolism of maltose, an intermediate on the pathway by which starch is converted to sucrose at night. In in vitro assays, the enzyme utilizes glycogen as a glucosyl acceptor but the in vivo acceptor molecules remained unknown. In this communication we present evidence that DPE2 acts on the recently identified cytosolic water‐soluble heteroglycans (SHG) as does the cytosolic phosphorylase (EC 2.4.1.1) isoform. By using in vitro two‐step 14C labeling assays we demonstrate that the two transferases can utilize the same acceptor sites of the SHG. Cytosolic heteroglycans from a DPE2‐deficient Arabidopsis mutant were characterized. Compared with the wild type the glucose content of the heteroglycans was increased. Most of the additional glucosyl residues were found in the outer chains of SHG that are released by an endo‐α‐arabinanase (EC 3.2.1.99). Additional starch‐related mutants were characterized for further analysis of the increased glucosyl content. Based on these data, the cytosolic metabolism of starch‐derived carbohydrates is discussed.

Journal

The Plant JournalWiley

Published: May 1, 2006

Keywords: ; ; ; ; ;

There are no references for this article.