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HPPD is an enzyme that usually bonds to form tetramers in bacteria and dimers in eukaryotes and has a subunit mass of 40-50 kDa. [7] [8] [9] Dividing the enzyme into the N-terminus and C-terminus one will notice that the N-terminus varies in composition while the C-terminus remains relatively constant [10] (the C-terminus in plants does differ slightly from the C-terminus in other beings).
4-Hydroxyphenylpyruvate dioxygenase (HPPD) is an enzyme found in both plants and animals, which catalyzes the catabolism of the amino acid tyrosine. [4] Preventing the breakdown of tyrosine has three negative consequences: the excess of tyrosine stunts growth; the plant suffers oxidative damage due to lack of tocopherols (vitamin E); and ...
The mechanism of action of nitisinone involves inhibition of 4-Hydroxyphenylpyruvate dioxygenase (HPPD). [5] [6] This is a treatment for patients with Tyrosinemia type 1 as it prevents the formation of 4-Maleylacetoacetic acid and fumarylacetoacetic acid, which have the potential to be converted to succinyl acetone, a toxin that damages the liver and kidneys. [4]
Tyrosinemia type III is a rare disorder caused by a deficiency of the enzyme 4-hydroxyphenylpyruvate dioxygenase (EC 1.13.11.27), encoded by the gene HPD. [2] This enzyme is abundant in the liver, and smaller amounts are found in the kidneys. It is one of a series of enzymes needed to break down tyrosine.
[1] [2] Normally, the breakdown of the amino acid tyrosine involves the conversion of 4-hydroxyphenylpyruvate to homogentisate by 4-hydroxyphenylpyruvate dioxygenase. Complete deficiency of this enzyme would lead to tyrosinemia III. In rare cases, however, the enzyme is still able to produce the reactive intermediate 1,2-epoxyphenyl acetic acid ...
As the hydroxylase adds a hydroxyl (the −OH group), the labeled site shifts one position around the aromatic ring relative to the stationary methyl group (−CH 3). Several hydroxylase enzymes are believed to incorporate an NIH shift in their mechanism, including 4-hydroxyphenylpyruvate dioxygenase and the tetrahydrobiopterin dependent ...
In enzymology, a 4-hydroxymandelate synthase (EC 1.13.11.46) is an enzyme that catalyzes the chemical reaction. 4-hydroxyphenylpyruvate + O 2 4-hydroxymandelate + CO 2. Thus, the two substrates of this enzyme are 4-hydroxyphenylpyruvate and oxygen, whereas its two products are 4-hydroxymandelate and carbon dioxide.
4-Hydroxyphenylpyruvate:oxygen oxidoreductase may refer to: 4-hydroxyphenylpyruvate dioxygenase; 4-hydroxymandelate synthase