Inactivation of barley limit dextrinase inhibitor by thioredoxin-catalysed disulfide reduction

Johanne Mørch Jensen, Per Hägglund, Hans Erik Mølager Christensen, Birte Svensson

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Barley limit dextrinase (LD) that catalyses hydrolysis of α-1,6 glucosidic linkages in starch-derived dextrins is inhibited by limit dextrinase inhibitor (LDI) found in mature seeds. LDI belongs to the chloroform/methanol soluble protein family (CM-protein family) and has four disulfide bridges and one glutathionylated cysteine. Here, thioredoxin is shown to progressively reduce disulfide bonds in LDI accompanied by loss of activity. A preferential reduction of the glutathionylated cysteine, as indicated by thiol quantification and molecular mass analysis using electrospray ionisation mass spectrometry, was not related to LDI inactivation. LDI reduction is proposed to cause conformational destabilisation leading to loss of function.
Original languageEnglish
JournalF E B S Letters
Volume586
Issue number16
Pages (from-to)2479-2482
ISSN0014-5793
DOIs
Publication statusPublished - 2012

Keywords

  • Thioredoxin h
  • Starch mobilisation
  • Seed germination
  • Glutathione
  • Electrospray ionisation mass spectrometry

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