Reaction Mechanism of Human Glutathione Reductase
NADPH reduces FAD present in GSR to produce a transient FADH- anion. This anion then quickly breaks a disulfide bond (Cys58 - Cys63) and leads to Cys63's nucleophilically attacking the nearest sulfide unit in the GSSG molecule (promoted by His467), which creates a mixed disulfide bond (GS-Cys58) and a GS- anion. His467 of GSR then protonates the GS- anion to form the first GSH. Next, Cys63 nucleophilically attacks the sulfide of Cys58, releasing a GS- anion, which, in turn, picks up a solvent proton and is released from the enzyme, thereby creating the second GSH. So, for every GSSG and NADPH, two reduced GSH molecules are gained, which can again act as antioxidants scavenging reactive oxygen species in the cell.
Read more about this topic: Glutathione Reductase
Famous quotes containing the words reaction, mechanism and/or human:
“An actor must communicate his author’s given message—comedy, tragedy, serio- comedy; then comes his unique moment, as he is confronted by the looked-for, yet at times unexpected, reaction of the audience. This split second is his; he is in command of his medium; the effect vanishes into thin air; but that moment has a power all its own and, like power in any form, is stimulating and alluring.”
—Eleanor Robson Belmont (1878–1979)
“The law isn’t justice. It’s a very imperfect mechanism. If you press exactly the right buttons and are also lucky, justice may show up in the answer. A mechanism is all the law was ever intended to be.”
—Raymond Chandler (1888–1959)
“The truth has never been of any real value to any human being—it is a symbol for mathematicians and philosophers to pursue. In human relations kindness and lies are worth a thousand truths.”
—Graham Greene (1904–1991)