Hydrogen Sulphide Flashcards
what is hydrogen sulphide?
a messenger molecule that is extremely toxic
describe h2s in a solution?
within a solution hydrogen sulphide is ionised
what are the biological sources of h2s?
hydrogen sulphide comes from three cysteine enzymes: CSE, CBS, 3-MST
what are two extra biological sources of hydrogen sulphide?
intestinal flora
iron-sulphur clusters
what is sulfyhdration?
the addition of a sulphur to a cysteine residue to form sulphur rings
what is evidence for the function of H2S in the cardiovascular system?
CSE enzyme knockout in mice shows hypertension and impaired vasodilation
what is the functions of H2S in the cardiovascular system?
enhances K-atp channels
inhibitis phosphodiesterases
what is dysregulated H2S biosynthesis?
it occurs during pregnancy in maternal hypertension and preeclampsia
describe H2S in the gut…
in the gut, hydrogen sulphide is produced by resident microbes and is involved in smooth muscle relaxation, protecting against inflammation, ischemic damage protection, and protecting from alcohol-induced gastritis
describe the distribution of H2S synthesis enzymes in the nervous system
in the nervous system, CBS enzymes are found in glia and astrocytes, and CSE and 3-MST enzymes are found in neurons - the multiple sources for hydrogen sulphide indicate its importance within the nervous system
describe the different roles hydrogen sulphide plays in the central nervous system…
involved in long term potentiation (as this process most likely occurs by sulfhydration)
dysregulation of the hydrogen sulphide metabolism is also present in ASD and PD
what is synergy?
the interaction or cooperation of two or more substances to produce an outcome which is greater than the sum of their individual effects.
what synergetic relationships exist between hydrogen sulphide and nitric oxide?
in the aorta, low concentrations of hydrogen sulphide increase nitric oxide induced smooth muscle relaxation
describe the synergy between hydrogen sulphide and nitric oxide…
the enzymes which produce H2S and NO are co-located. HSH could react with nitrite to produce HSNO
what is thionitrous acid?
HSNO, produced by co-localised reaction of HSH with nitrite
