The liver drills a handle then welds a water tag; past saturation the intermediate gets a window.
Full mechanism, in text
Why the dose makes the poison
1 · A foreign molecule in blood has two exits
A foreign molecule has two exits, the kidney into urine and the liver into bile, but most are lipophilic and dissolve back into blood after the kidney filters them.The kidney filters it into urine; the liver throws it into bile. Most foreign molecules are lipophilic: the tubule filters them into urine, and they dissolve back into blood through the wall. Filter once, return once. The kidney alone struggles to get rid of them.
2 · The liver drills a handle first
Liver P450 enzymes stamp an oxygen onto the foreign molecule to drill a handle, and this oxidation often yields an intermediate far more reactive than the original.A family of enzymes in the hepatocyte (cytochrome P450) stamps an oxygen onto it, making a handle that can take a tag. Drilling the handle is oxidation, and the intermediate is often far more reactive than the original molecule.
3 · Weld a water tag, and it can leave
Another set of enzymes hangs a large, water-loving, charged tag on the handle, so the molecule can no longer cross membranes and leaves in urine once filtered.Another set of enzymes hangs a large, water-loving, charged tag on the handle. After that it has changed character: heavy, charged, hydrophilic, it cannot crawl back through a membrane, and once the kidney filters it, it can only leave in urine. Detox is not destroying it. It is reshaping it so it can leave.
4 · Saturate the line and the intermediate gets a window
Enzymes have a speed ceiling and excess piles up, but once liver enzymes activate aflatoxin, even a tiny amount sends some into DNA, no saturation needed.Enzymes are finite and each has a speed ceiling. Saturate them and what comes next piles up. For many molecules, the question is not whether the molecule is toxic but whether this amount exceeds the speed at which the body clears it. Aflatoxin is not one of them: it arrives at the liver fairly harmless, and enzymes in the liver itself activate it into a highly reactive molecule that lodges in DNA. The human liver has little of the enzyme that intercepts that molecule, so the line never needs to saturate: even a tiny amount sends some of it into DNA. That is why regulators set no tolerable daily intake for it and ask only for as little as possible.