Metallothionein (MT) is a cysteine-rich protein with a low molecular weight. They are found in the membrane of the Golgi apparatus.
MTs have the capacity to bind to certain minerals and heavy metals, both physiological minerals and xenobiotic heavy metals:
There are four main isoforms of MTs expressed in humans, where large quantities are synthesized primarily in the liver and kidneys:
- MT-1 & MT-2 – Found ubiquitously throughout the body
- MT-3 – Found primarily in the brain
- MT-4 – Found in epithelial tissues, esophagus, GI tract, upper stomach, and skin
The production of MTs in the body require certain minerals and amino acids:
In addition to MT’s ability to sequester heavy metals, they are also capable of scavenging free radicals and inhibiting inflammation:
Exposure to heavy metals can create a low level of MTs in the kidneys and liver. Increased MT synthesis is associated with increased capacity for binding these heavy metals and protection against metal toxicity. Certain foods and nutrients have been shown to induce and increase the levels of MTs in the body.
- cruciferous vegetables (sulforaphane) (MT-1/2 and MT-1a were increased up to 10-fold by 2 to 4 hours after sulforaphane dosing 6