4-Hydroxyphenylpyruvic acid (4-HPPA) is an intermediate in the metabolism of the amino acid
phenylalanine
Phenylalanine (symbol Phe or F) is an essential α-amino acid with the formula . It can be viewed as a benzyl group substituted for the methyl group of alanine, or a phenyl group in place of a terminal hydrogen of alanine. This essential amino a ...
. The aromatic side chain of phenylalanine is hydroxylated by the enzyme
phenylalanine hydroxylase to form
tyrosine
-Tyrosine or tyrosine (symbol Tyr or Y) or 4-hydroxyphenylalanine is one of the 20 standard amino acids that are used by cells to synthesize proteins. It is a non-essential amino acid with a polar side group. The word "tyrosine" is from the Gr ...
. The conversion from tyrosine to 4-HPPA is in turn catalyzed by
tyrosine aminotransferase
Tyrosine aminotransferase (or tyrosine transaminase) is an enzyme present in the liver and catalyzes the conversion of tyrosine to 4-hydroxyphenylpyruvate.
L-tyrosine + 2-oxoglutarate \rightleftharpoons 4-hydroxyphenylpyruvate + L-glutamate
...
. Additionally, 4-HPPA can be converted to
homogentisic acid which is one of the precursors to
ochronotic pigment
Ochronosis is a syndrome caused by the accumulation of homogentisic acid in connective tissues. The condition was named after the yellowish (ocher-like) discoloration of the tissue seen on microscopic examination. Macroscopically, though, the af ...
.
It is an intermediary compound in the biosynthesis of
scytonemin.
See also
*
4-Hydroxyphenylpyruvate dioxygenase
4-Hydroxyphenylpyruvate dioxygenase (HPPD), also known as α-ketoisocaproate dioxygenase (KIC dioxygenase), is an Fe(II)-containing non-heme oxygenase that catalyzes the second reaction in the catabolism of tyrosine - the conversion of 4-hydro ...
References
Natural phenols
Phenols
Alpha-keto acids
Propionic acids
Hydroxy acids
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