Quecksilber: the pathway in the body

Quecksilber is part of the pathway “Quecksilber”. This page shows the whole pathway; the station of Quecksilber is highlighted.

Where this laboratory value sits: Forms of mercury — vapour, salts, methyl-Hg. Mercury occurs in three forms: as vapour, which passes into the blood via the lung, as an inorganic salt, and as methylmercury, which reaches the gut with food. Source 1

In brief

Mercury is a heavy metal that occurs as vapour, as inorganic salt and as methylmercury. In the body it binds tightly to sulfur and selenium groups of proteins and leaves via bile, stool and urine.

The pathway step by step

1. Forms of mercury → Methylmercury · L-cysteine Methylmercury is absorbed almost completely in the gut. In the body it is bound to thiols, for example to the amino acid L-cysteine. Source 1, 2
2. Forms of mercury → Inorganic mercury Catalase Inhaled mercury vapour is oxidised to mercury ions by the enzyme catalase in the red blood cells. In blood these ions bind to thiols and proteins. Source 1
3. Methylmercury → Into tissues LAT1 The complex of methylmercury and L-cysteine resembles the amino acid methionine. The amino acid transporter LAT1 therefore carries it into cells, including across the blood-brain barrier. Source 3, 2
4. Inorganic mercury → Kidney OAT1 · cysteine, glutathione The kidney takes in mercury ions as a complex with cysteine or glutathione, among other routes via the transporter OAT1. There it binds to metallothionein. Source 4, 2
5. Into tissues → Metallothionein In tissues, methylmercury is slowly converted to mercury ions. These bind to metallothionein, a small protein with many cysteines that also binds zinc. Source 1, 4
6. Hg on thiol groups → Selenoproteins · Selenocysteine Mercury binds even more tightly to the selenol group of selenocysteine. This amino acid sits in the active site of enzymes such as thioredoxin reductase and glutathione peroxidase. Source 7, 6
7. Selenoproteins → Hg-selenium compound · Selenium Mercury and selenium form poorly soluble compounds. Selenium bound in this way is no longer available for building new selenoproteins. Source 6
8. Hg on thiol groups → Hg-glutathione complex · Glutathione In the liver cell, mercury binds to glutathione. This complex is the form in which it can leave the cell. Source 5, 1
9. Hg-glutathione complex → Bile MRP2 The transporter MRP2 releases the glutathione complex into the bile. In this way methylmercury reaches the gut. Source 5, 1
10. Bile → Gut gut bacteria Gut bacteria convert part of the methylmercury into inorganic mercury, which leaves with the stool. The rest can be absorbed again. Source 1

Cofactors in this pathway

• Selenium — Sits as selenocysteine at the centre of selenoenzymes; mercury binds it tightly Source 6, 7In the ORY catalogue as a laboratory value: Selen
• Glutathione — Forms a complex with mercury that MRP2 exports from the cell into the bile Source 5, 1In the ORY catalogue as a laboratory value: Glutathion (GSH)
• L-cysteine — Forms a complex with methylmercury that LAT1 carries like an amino acid Source 3, 2
• Methionine — The methylmercury-cysteine complex resembles methionine and uses its transporter Source 3In the ORY catalogue as a laboratory value: Methionin
• Zinc — Is bound, like mercury, by the cysteines of metallothionein Source 4In the ORY catalogue as a laboratory value: Zink

Sources

1. Clarkson TW, Magos L. The toxicology of mercury and its chemical compounds. Crit Rev Toxicol 2006 · PubMed 16973445
2. Bridges CC, Zalups RK. Molecular and ionic mimicry and the transport of toxic metals. Toxicol Appl Pharmacol 2005 · PubMed 15845419
3. Simmons-Willis TA, Koh AS et al. Transport of a neurotoxicant by molecular mimicry: the methylmercury-L-cysteine complex is a substrate for human L-type large neutral amino acid transporter (LAT) 1 and LAT2. Biochem J 2002 · PubMed 12117417
4. Zalups RK. Molecular interactions with mercury in the kidney. Pharmacol Rev 2000 · PubMed 10699157
5. Ballatori N, Clarkson TW. Biliary secretion of glutathione and of glutathione-metal complexes. Fundam Appl Toxicol 1985 · PubMed 4065458
6. Ralston NVC, Raymond LJ. Mercury's neurotoxicity is characterized by its disruption of selenium biochemistry. Biochim Biophys Acta Gen Subj 2018 · PubMed 29753115
7. Branco V, Carvalho C. The thioredoxin system as a target for mercury compounds. Biochim Biophys Acta Gen Subj 2019 · PubMed 30447253

Whole pathway: Quecksilber

Related pathways

• Arsen — Selen, Glutathion (GSH)
• Blei — Glutathion (GSH), Zink
• Cadmium — Glutathion (GSH), Zink
• Nickel — Glutathion (GSH), Zink

As of 2026-09-18. Draft, written by Claude to schema v2; sources checked in PubMed; expert approval pending
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