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

► Trxh reduces all five disulfide bonds in barley LDI causing inactivation. ► LDI is protected against Trxh reduction when complexed to LD. ► Trxh shows preference for the glutathionylated cysteine disulfide in LDI. ► Deglutathionylation appears not to be connected with inactivation of LDI. ► Conformational destabilisation of LDI is proposed to cause inactivation.