Endogenous hydrogen sulfide (H2S) is up-regulated during sweet pepper (Capsicum annuum L.) fruit ripening. In vitro analysis shows that NADP-dependent isocitrate dehydrogenase (ICDH) activity is inhibited by H2S and nitric oxide

Publication date: Available online 13 October 2018Source: Nitric OxideAuthor(s): María A. Muñoz-Vargas, Salvador González-Gordo, Amanda Cañas, Javier López-Jaramillo, José M. Palma, Francisco J. CorpasAbstractLike nitric oxide (NO), hydrogen sulfide (H2S) has been recognized as a new gasotransmitter which plays an important role as a signaling molecule in many physiological processes in higher plants. Although fruit ripening is a complex process associated with the metabolism of reactive oxygen species (ROS) and nitrogen oxygen species (RNS), little is known about the potential involvement of endogenous H2S. Using sweet pepper (Capsicum annuum L.) as a model non-climacteric fruit during the green and red ripening stages, we studied endogenous H2S content and cytosolic l-cysteine desulfhydrase (L-DES) activity which increased by 14% and 28%, respectively, in red pepper fruits. NADPH is a redox compound and key cofactor required for cell growth, proliferation and detoxification. We studied the NADPH-regenerating enzyme, NADP-isocitrate dehydrogenase (NADP-ICDH), whose activity decreased by 34% during ripening. To gain a better understanding of its potential regulation by H2S, we obtained a 50–75% ammonium sulfate-enriched protein fraction containing the NADP-ICDH protein; with the aid of in vitro assays in the presence of H2S, we observed that 2 and 10 mM NaHS used as H2S donors resulted in a decrease of up to 36% and 45%, respectively, in NADP-ICDH activity, which wa...
Source: Nitric Oxide - Category: Chemistry Source Type: research