| Summary: | In higher plants, hydrogen sulfide (H<sub>2</sub>S) is a recognized signaling molecule that performs multiple regulatory functions. The enzyme L-cysteine desulfhydrase (LCD) catalyzes the conversion of L-cysteine (L-Cys) to pyruvate and ammonium with the concomitant generation of H₂S, and it is considered one of the main sources of H<sub>2</sub>S in plants. Using non-denaturing polyacrylamide gel electrophoresis (PAGE) in combination with a specific assay for LCD activity, this study aims to identify the potential LCD isozymes in wild-type <i>Arabidopsis thaliana</i> seedlings of 16 days old grown under in vitro conditions, and to evaluate the potential impact of nitric oxide (NO) and H<sub>2</sub>S on these LCD isozymes. For this purpose, an <i>Atnoa1</i> mutant characterized to have a low endogenous NO content as well as the exogenous application of H<sub>2</sub>S were used. Five LCD isozymes were detected, with LCD IV being the isozyme that has the highest activity. However, the LCD V activity was the only one that was positively modulated in the <i>Atnoa1</i> mutants and by exogenous H<sub>2</sub>S. To our knowledge, this is the first report showing the different LCD isozymes present in Arabidopsis seedlings and how their activity is affected by NO and H<sub>2</sub>S content.
|
|---|