Purification, characterization and identification of a senescence related serine protease in dark-induced senescent wheat leaves.

Renxian Wang, Shaowei Liu, Jin Wang, Qiang Dong, Langlai Xu, Qi Rui

Index: Phytochemistry 95 , 118-26, (2013)

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Abstract

Senescence-related proteases play important roles in leaf senescence by regulating protein degradation and nutrient recycling. A 98.9kDa senescence-related protease EP3 in wheat leaves was purified by ammonium sulfate precipitation, Q-Sepharose fast flow anion exchange chromatography and gel slicing after gel electrophoresis. Due to its relatively high thermal stability, its protease activity did not decrease after incubation at 40°C for 1-h. EP3 protease was suggested to be a metal-dependent serine protease, because its activity was inhibited by serine protease inhibitors PMSF and AEBSF and metal related protease inhibitor EGTA. It was identified as a subtilisin-like serine protease of the S8A family based on data from both mass spectrometry and the cloned cDNA sequence. Therefore, these data suggest that a serine protease of the S8A subfamily with specific biochemical properties is involved in senescence-associated protein degradation. Copyright © 2013 Elsevier Ltd. All rights reserved.