"Cutler's book covers the subject of thiol groups and methyl groups, yes? May need to go back and read it afresh.
== The search feature in the Googlebooks version is quite handy, especially along with the hard copy
"Can you say if DMSA has the same effect of lowering homocysteine levels as TMG?
== I'm not aware that DMSA lowers homocysteine in the short term. The effect of lowering levels of heavy metals probably would help in the long term.
== My understanding is that methionine synthase (MS) is one of the zinc dependent enzymes vulnerable to heavy metals. Notice that Zn is in the same column of the Periodic Table as mercury and cadmium. Therefore they compete to some extent.