The influence on DNA can cause the increased frequency of cancer observed after exposure to mustard agent. The other mechanism of action is interaction between mustard agent and intracellular glutathion. Glutathion is a small peptide molecule which, among other things, takes care of the free radicals formed during cell respiration. If too large an amount of glutathion is bound by mustard agent, then the regulation of these free radicals no longer functions. Since free radicals are extremely toxic, this may lead to a number of processes in the cell being severely disturbed.
Mustard agent can also bind to different proteins in the cell.
However, it is not known how much this contributes to the injuries caused. The binding takes place at the functional groups, e.g., the sulphydryl or amino groups. If the binding is made to, for example, the active site of enzymes, then their activity is inhibited which could lead to metabolic disorders. If, on the other hand, membrane proteins are bound, the result can be a modified uptake of substances and the inner environment of the cell will become disturbed.