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          Institute: MPI für molekulare Pflanzenphysiologie     Collection: Publikationen Pflanzenphysiologie     Display Documents

ID: 230004.0, MPI für molekulare Pflanzenphysiologie / Publikationen Pflanzenphysiologie
The glycan substrate of the cytosolic (Pho 2) phosphorylase isozyme from Pisum sativum L.: identification, linkage analysis and subcellular localization
Authors:Fettke, J.; Eckermann, N.; Poeste, S.; Pauly, M.; Steup, M.
Date of Publication (YYYY-MM-DD):2004-09
Title of Journal:Plant Journal
Journal Abbrev.:Plant J
Issue / Number:6
Start Page:933
End Page:946
Review Status:not specified
Audience:Not Specified
Abstract / Description:The subcellular distribution of starch-related enzymes and the phenotype of Arabidopsis mutants defective in starch degradation suggest that the plastidial starch turnover is linked to a cytosolic glycan metabolism. In this communication, a soluble heteroglycan (SHG) from leaves of Pisum sativum L. has been studied. Major constituents of the SHG are galactose, arabinose and glucose. For subcellular location, the SHG was prepared from isolated protoplasts and chloroplasts. On a chlorophyll basis, protoplasts and chloroplasts yielded approximately 70% and less than 5%, respectively, of the amount of the leaf-derived SHG preparation. Thus, most of SHG resides inside the cell but outside the chloroplast. SHG is soluble and not membrane-associated. Using membrane filtration, the SHG was separated into a <10 kDa and a >10 kDa fraction. The latter was resolved into two subfractions (I and II) by field-flow fractionation. In the protoplast-derived >10 kDa SHG preparation the subfraction I was by far the most dominant compound. beta-Glucosyl Yariv reagent was reactive with subfraction II, but not with subfraction I. In in vitro assays the latter acted as glucosyl acceptor for the cytosolic (Pho 2) phosphorylase but not for rabbit muscle phosphorylase. Glycosidic linkage analyses of subfractions I and II and of the Yariv reagent reactive glycans revealed that all three glycans contain a high percentage of arabinogalactan-like linkages. However, SHG possesses a higher content of minor compounds, namely glucosyl, mannosyl, rhamnosyl and fucosyl residues. Based on glycosyl residues and glycosidic linkages, subfraction I possesses a more complex structure than subfraction II.
Free Keywords:polysaccharide metabolism
; maltose metabolism
; phosphorylase
; heteroglycan
; cytosol
; pisum sativum
; solanum-tuberosum l.
; arabinogalactan-proteins
; starch degradation
; spinach leaves
; maltose
; plants
; affinophoresis
; photosynthesis
; biosynthesis
; chloroplast
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für molekulare Pflanzenphysiologie/Unabhängige Nachwuchsgruppen/AG Pauly
External Affiliations:Univ Potsdam, Dept Plant Physiol, Inst Biochem & Biol, Karl Liebknecht Str 24-25,Bldg 20, D-14476 Potsdam, Germany
Univ Potsdam, Dept Plant Physiol, Inst Biochem & Biol, D-14476 Potsdam, Germany
Max Planck Inst Mol Plant Physiol, D-14476 Potsdam, Germany
Identifiers:ISI:000224178500011 [ID No:1]
ISI:000224178500011 [ID No:2]
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