The former enzyme is the phenylalanine hydroxylase, and the sheep enzyme catalyzes a reaction involving TPNH which serves to maintain the cofactor in the active, reduced form. The assay of the enzyme system is based on a colorimetric determination of tyrosine by a modification of the nitroso...
Tetrahydrobiopterin is an essential cofactor for the phenylalanine hydroxylase enzyme. In the course of the reaction, BH4 is oxidized to dihydrobiopterin, and it must be reduced with NADH in a reaction catalyzed by dihydropteridine reductase. Patients may have defects in this enzyme or in the syn...
phenylalanine hydroxylase 听听怎么读 [ˌfenəlˈæləni:n haiˈdrɔksileis] 是什么意思 释义 [医]苯丙氨酸羟化酶; 英英释义 Phenylalanine hydroxylase Phenylalanine hydroxylase (PheOH, alternatively PheH or PAH) () is an enzyme that catalyzes the hydroxylation of the aromatic side-chain...
enzyme mechanismshydroxylasesmeta-tyrosine biosynthesis1,2-hydride (NIH) shiftThe rare non﹑roteinogenic amino acid, metaL‐tyrosine is biosynthetically intriguing. Whilst the biogenesis of tyrosine from phenylalanine is well characterised, the mechanistic basis for meta﹉ydroxylation is unknown. Herein,...
Phenylalanine hydroxylase (PAH) is a key tyrosine-biosynthetic enzyme involved in neurological and melanin-associated physiological processes. Despite extensive investigations in holometabolous insects, a PAH contribution to insect embryonic development
Phenylalanine ammonia lyase is a bacterial enzyme that degrades PHE to trans- cinnamic acid; trans-cinnamic acid and its final product, ben- zoic acid, are conjugated with glycine and excreted in the urine. Eventually, treatment of PAH deficiency will be individual- ized with multiple medications...
Phenylalanine hydroxylase (PH; EC 1.14.16.1) is a complex enzyme with three substrates and three activators. Little is known about the structural features which are necessary for the function of this enzyme; only the phosphorylation site is known (Wretburn et al ., 1980). We have recently ...
It appears in large amount in urine of patients with phenylketonuria which is a human genetic disorder due to the lack of phenylalanine hydroxylase, the enzyme necessary to metabolize phenylalanine to tyrosine. Acetylphenylalanine is a product of enzyme phenylalanine N-acetyltransferase in the pathway ...
Phenylalanineis anessential amino acid. It is normally degraded via thetyrosinepathway. To enter the tyrosine pathway,phenylalanineis converted into tyrosine by theenzymephenylalanine hydroxylase, which hastetrahydrobiopterinas a cofactor. Deficiency of the enzyme or of its cofactor causes accumulation ofphe...
With the flavin dependent hydroxylases the step involving formation of the C4a-hydroperoxide intermediate by interaction of oxygen with reduced enzyme is not rate limiting (1,2). However, with the tetrahydrobiopterin dependent phenylalanine hydroxylase from rat liver there is a strong correlation between...