Journal of Agricultural and Food Chemistry 2009-09-09

Triosephosphate isomerases in Italian ryegrass ( Lolium multiflorum ): characterization and susceptibility to herbicides.

Daniele Del Buono, Bhakti Prinsi, Luca Espen, Luciano Scarponi

Index: J. Agric. Food Chem. 57(17) , 7924-30, (2009)

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Abstract

The effect of treatments with four herbicides and a safener on the activity of triosephosphate isomerase (TPI) extracted from shoots of Italian ryegrass was investigated. It was found that atrazine and fluorodifen, herbicides which interfere with photosynthesis, caused a decrease in measured enzyme activity. In addition, the in vitro effect of oxidized glutathione (GSSG), a compound produced in situations of oxidative stress, on TPI activity was investigated. It was shown that GSSG was a strong inhibitor of enzyme activity, at low concentrations in a dose-time-dependent manner. The enzyme extracts were submitted to chromatographic purifications and to two-dimensional electrophoresis. Some spots had molecular masses ranging between 20 and 30 kDa and were characterized and identified by LC-ESI-MS/MS as TPIs. The mass spectrometry also made it possible to identify the presence of cysteine residues that could be subjected to S-glutathionylation, which regulate the enzyme activity.