Ricerc@Sapienza

Cytochrome bd is a prokaryotic respiratory terminal oxidase phylogenetically unrelated to haem-copper oxidases. In addition to sustaining energy metabolism, this enzyme is implicated in bacterial protection against oxidative and nitrosative stress. Cytochrome bd is only found in prokaryotes and, as it promotes virulence in several pathogenic bacteria, it is currently recognized as a potential drug target.

Hydrogen sulfide (H2S) plays key roles in human (patho)physiology. Synthesized endogenously by known enzymatic systems, H2S is mainly metabolized through a mitochondrial sulfide-oxidizing pathway that comprises sulfide:quinone oxidoreductase (SQR) and a few other enzymes. H2S degradation through this pathway is coupled to electron injection into the respiratory chain and, thus, to stimulation of ATP synthesis. In cancer cells, H2S was reported to be synthesized at high levels and to stimulate energy metabolism and cell proliferation.

Sulfane sulfur species comprise a variety of biologically relevant hydrogen sulfide (H2S)-derived species, including per- and poly-sulfidated low molecular weight compounds and proteins. A growing body of evidence suggests that H2S, currently recognized as a key signaling molecule in human physiology and pathophysiology, plays an important role in cancer biology by modulating cell bioenergetics and contributing to metabolic reprogramming.

Thiotaurine, a thiosulfonate related to taurine and hypotaurine, is formed by a metabolic process from cystine and generated by a transulfuration reaction between hypotaurine and thiocysteine. Thiotaurine can produce hydrogen sulfide (H2S) from its sulfane sulfur moiety. H2S is a gaseous signaling molecule which can have regulatory roles in inflammatory process. In addition, sulfane sulfur displays the capacity to reversibly bind to other sulfur atoms. Thiotaurine inhibits PMA-induced activation of human neutrophils, and hinders neutrophil spontaneous apoptosis.

Hydrogen sulfide (H2S), a key signalling molecule in human patho-physiology, is produced by the human enzymes cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE) and 3-mercaptopyruvate sulfurtransferase (MST). Increasing evidence indicates a correlation between increased H2S production and human diseases, such as several cancer types and amyotrophic lateral sclerosis. Identifying selective and potent inhibitors may be beneficial for future therapeutic strategies.