It is known that the covalent bonds are very strong with a high bond dissociation energy. In a document related to University of Illinois website about this issue (http://www.life.illinois.edu/mcb/150/private/faq/index.php?sid=62416&lang=en&action=artikel&cat=4&id=1110&artlang=en), I found this note " In the laboratory setting, if a researcher wants to denature a protein with disulfide bonds he or she adds a special chemical reducing agent that breaks the disulfide bond to insure that the protein denatures completely". My question is in which conditions can molecular hydrogen (H2) break the disulfide bond in proteins?
No, at least not under the conditions encountered in a protein chemistry lab. Instead, glutathion (GSH), ß-mercaptoethanol (BME) or (better) dithiotreitol (DTT, Cleland's reagent) will do the job for you.
Dear Engelbert Buxbaum thank you for your answer. However, if I want to use molecular hydrogen to break disulfide bond of protein, what will be the environment conditions (temperature, pressure, etc) recommended to breaking this bond? Have you any idea?
thanks
Hydrotreating sulfur containing hydrocarbons to convert S compounds to H2S + remaining hydrocarbon (and saturating any olefins ) has been done commercially for over 100 years. Usually catalyzed with CoMo or NiMo catalyst..
Dear Sebastian Schmitt
and Rick Manner Thank you for your answer. My goal is to inactivate disulfide-contained enzymes by using molecular hydrogen. I have read some papers (see the attached ones) that explain the change in the S-S/S ratio in vitro assays when molecular hydrogen was applied.I need to learn more about the possibility to use molecular hydrogen treatment in the inactivation of disulfide-contained enzymes. What will be the environmental conditions to realize these assays?
Dear Engelbert Buxbaum why glutathion , ß-mercaptoethanol dithiotreitol can break disulfide bond but not molecular hydrogen? although the H2 is more strong reducing compound than DTT for example?
There are three factors that affect reaction rates: the Gibbs free energy, the activation energy and the concentration. The solubility of hydrogen in water is low (0.8 mM at a partial pressure of 1 bar, with a Henry constant of KH = 1282 bar M-1). The next problem will be the activation energy probably determined mostly by the bond dissociation energy of the H-H bond (436 kJ/mol, which is why Sebastian Schmitt
spoke of nascending hydrogen). Don't get me wrong: it can be done, but only at temperatures and pressures that are not healthy for your protein.
Dear Engelbert Buxbaum thank you for your answer. As I said before, my goal is to inactivate enzymes, so the denaturation of protein is a good thing in this issue. the denaturation of enzyme protein will lead to inactivate the enzyme itself. I have performed some experiments on the effect of H2 on polyphenol oxidase activity under normal room conditions but we have not shown any inhibition effects. We think to use high-pressure H2 treatment for this goal but we don't know how much pressure/temperature we must apply. So, can the pressured H2 break the disulfide bonds? how many bars we must apply?
Dear Engelbert Buxbaum , Rick Manner, and Sebastian Schmitt
can you please participate in the new discussion platformer about the subject of the disulfide bond and molecular hydrogen at the following link:https://www.researchgate.net/post/Molecular_Hydrogen_Effect_on_Disulfide_Bond
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