Negative feedback in the fructose metabolism in liver What happens in liver when large amount of fructose is consumed? I vaguely remember my biochemistry lecturer telling us that the enzymes that process fructose in the liver does not have negative feedback to control the rate of reaction. But I cannot find a reliable source. How is it regulated if it is?

The main reaction of fructose in liver is phosphorylation, catalyzed by ketohexokinase (UniProt P50053). In one paper with rats it was shown that fructose load can deplete the liver of nucleotide triphosphates (ATP, GTP) although ADP and GDP are inhibitors of the enzyme. This shows there is no effective regulation.

M. I. Phillips, D. R. Davies: _The mechanism of guanosine triphosphate depletion in the liver after a fructose load. The role of fructokinase._ In: _The Biochemical journal._ Vol 228, Nr 3, Jun 1985, p. 667–671, {{ISSN|0264-6021}}. PMID 2992452. PMC 1145036.