Figure 5–

The fate of Hg²⁺ from the diet, bleaching skin creams and those oxidized from Hg⁰ absorbed in the lungs. After entering the body, any free Hg²⁺ will rapidly react with free thiol groups. Here the low molecular mass thiol-containing molecules (LMM-SH molecules) are represented by cysteine (Cys₁-SH, Cys₂-SH or complexed with Hg²⁺ and other organic groups represented by G₂S−, Prt-S− or Prt-Se−). The complex Cys₁-S-Hg-S-Cys₁ can be absorbed from the intestinal tract and transported in the blood to the main target tissue (i.e., the kidney). (The molecular basis of why the kidney is the target organ of Hg²⁺ is elegantly reviewed in Zalups 2000). The reactions represented here can involve only one new thiol group (for instance, only one Cys₂-SH can react with the complex Cys₁-S-Hg-S-Cys₁ forming Cys₂-S-Hg-S-Cys₁ and Cys₁-SH as products and this applies to all the other thiols and complexes depicted in Figure 3.