4430 4-Hydroxyphenylpyruvic acid 4-Hydroxyphenylpyruvic acid (4-HPPA) is a keto acid that is involved in the tyrosine catabolism pathway. It is a product of the enzyme (R)-4-hydroxyphenyllactate dehydrogenase [EC 1.1.1.222] and is formed during tyrosine metabolism. The conversion from tyrosine to 4-HPPA is catalyzed by tyrosine aminotransferase. Additionally, 4-HPPA can be converted to homogentisic acid which is one of the precursors to ochronotic pigment. The enzyme 4-hydroxyphenylpyruvic acid dioxygenase (HPD) catalyzes the reaction that converts 4-hydroxyphenylpyruvic acid to homogentisic acid. A deficiency in the catalytic activity of HPD is known to lead to tyrosinemia type III, an autosomal recessive disorder characterized by elevated levels of blood tyrosine and massive excretion of tyrosine derivatives into urine. It has been shown that hawkinsinuria, an autosomal dominant disorder characterized by the excretion of 'hawkinsin,' may also be a result of HPD deficiency There are two isomers of HPPA, specifically 4HPPA and 3HPPA, of which 4HPPA is the most common. (A3451). 156-39-8 979 C9H8O4 White powder. 219 - 220°C No indication of carcinogenicity to humans (not listed by IARC). This is an endogenously produced metabolite found in the human body. It is used in metabolic reactions, catabolic reactions or waste generation. 2014-08-29T06:36:56Z 2026-05-14T18:45:19Z Hydroxyphenylpyruvic acid C01179 15999 P-HYDROXY-PHENYLPYRUVATE DB07718 ENO true OC(=O)C(=O)CC1=CC=C(O)C=C1 C9H8O4 InChI=1S/C9H8O4/c10-7-3-1-6(2-4-7)5-8(11)9(12)13/h1-4,10H,5H2,(H,12,13) KKADPXVIOXHVKN-UHFFFAOYSA-N 180.1574 180.042258744 Endogenous Solid 1.6 HMDB00707 CHEMBL607712 954 CHEM003336 DTXSID80166017 NS00015136 3-(4-hydroxyphenyl)-2-oxopropanoic acid 74.60000000000001 44.6925 16.750960680327967 3 4 2 2.91496710599853 -5.958513128269975 -1 1 1.12 -2.08 1.49e+00 g/l