reversible reaction

[ssh18]

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is the binding of substrate to an enzyme's active site reversible? it probably is but I'm just getting confused for some reason...
also the binding of a substrate to an allosteric site is reversible rite?


also, are coenzymes or co-factors considered prosthetic groups?

 

[killinsound]

Yes and no. Some toxins bind permanently to an enzyme's active site nullifying enzyme activity. Substrates *generally* bind reversibly.

 

[EBI831]

is the binding of substrate to an enzyme's active site reversible? it probably is but I'm just getting confused for some reason...
also the binding of a substrate to an allosteric site is reversible rite?


also, are coenzymes or co-factors considered prosthetic groups?

yes, substrate is supposed to be reversible if its a general substrate and not some sort of activator or inhibitor. substrate has to be reversible so that the enzyme isn't constitutively working and using up all the energy in the cell and when the functon its working toward isn't necessary for the cell. the binding to allosteric site is just binding somewhere that isn't the active site, it can be either reversible or irreversible i believe. a prosthetic group is a tightly bound cofactor that is usually inseparable from the enzyme. coenzymes are vitamins and the sort.

 

[wisguy]

All chemical reactions are technically reversible. Substrate/toxin binding is no exception. Relative binding/unbinding rates and probabilities based on thermodynamics determine whether we label a reaction irreversible or reversible. All enzymes have a spontaneous off rate (koff) for their substrate. For many enzymes this is quite low, so we say unbinding is irreversible, but in many other cases the substrate leaves the active site before the reaction begins other or other reactants are available.