EC Number   |
General Information |
Reference |
|---|
    1.13.11.27 | evolution |
4-hydroxyphenylpyruvate dioxygenase (HPPD) and hydroxymandelate synthase (HMS, EC 1.13.11.46) are outliers within the 2-oxo acid dependent oxygenase (aKAO) family. HPPD and HMS catalyze the chemistry of the majority of enzymes within the aKAO family but are clearly mechanistically convergent, having a grossly different structural topology. Some of the unique characteristics of HPPD and HMS have elucidated select parts of the catalytic cycle that are obscured in other family members. Moreover, the inhibitory chemistry of HPPD is a phenomenon with ever-expanding relevance across all kingdoms of life |
-, 741762 |
| 1.13.11.27 | evolution |
4-hydroxyphenylpyruvate dioxygenase and hydroxymandelate synthase, HMS, EC 1.13.11.46, catalyze similar reactions using the same substrates, 4-hydroxyphenylpyruvate and dioxygen. Initially, both enzymes reduce and activate dioxygen in order to decarboxylate 4-hydroxyphenylpyruvate, yielding 4-hydroxyphenylacetate, CO2, and an activated oxo intermediate Both enzymes then hydroxylate 4-hydroxyphenylacetate but do so in different positions |
724392 |
| 1.13.11.27 | evolution |
the enzyme belongs to the non-haem Fe(II)/2-oxoacid-dependent oxygenase superfamily, which couples the oxidative decarboxylation of a 2-oxoacid (most commonly a-ketoglutarate) to the oxidation of the prime substrate |
726347 |
| 1.13.11.27 | malfunction |
deficiency in active 4-HPPD in humans results in type III tyrosinemia, a rare autosomal recessive disorder |
726347 |
| 1.13.11.27 | malfunction |
inhibition of HPPD can effectively alleviate the symptoms of type I tyrosinemia |
742451 |
| 1.13.11.27 | malfunction |
mutant plants with null alleles of HPPD are reported to exhibit a lethal photobleaching phenotype. MsHPPD expression in three MsHPPD-overexpressing transgenic lines and wild-type, overview |
743829 |
| 1.13.11.27 | malfunction |
neutrophil preparations from a patient with tyrosinemia type III, with inherited deficiency of 4-hydroxyphenylpyruvate dioxygenase (HPPD), exhibit a far higher NO release than controls, when NO is estimated in terms of nitrite content in the suspending media. L-tyrosine increases nitrite release and accumulation in suspending media of U-937 cells, a human monoblast-like lymphoma cell line which displays many characteristics of macrophages, including the expression of inducible and endothelial nitric oxide synthases. The increase of nitrite release by patient's neutrophils might be related to the presence of high L-tyrosine concentrations in the blood samples rather than to HPPD deficiency of in these cells |
742056 |
| 1.13.11.27 | malfunction |
when HPPD is inhibited, the plant is severely damaged by sunlight, becoming bleached and eventually undergoing necrosis and death. HPPD inhibitors are termed bleaching herbicides |
743407 |
| 1.13.11.27 | metabolism |
4-ydroxyphenylpyruvate dioxygenase (HPPD) is an essential enzyme in tyrosine catabolism |
742451 |
| 1.13.11.27 | metabolism |
enzyme 4-HPPD catalyzes the second step in the pathway of tyrosine catabolism, the conversion of 4-hydroxyphenyl-pyruvate to homogentisate |
726347 |
