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Phenylalanine hydroxylase catalyzes the conversion of L-phenylalanine to L-tyrosine. Tyrosine hydroxylase catalyzes the rate-limiting step in catecholamine biosynthesis: the conversion of L-tyrosine to L-DOPA. Similarly, tryptophan hydroxylase catalyzes the rate-limiting step in serotonin biosynthesis: the conversion of L-tryptophan to 5 ...
Phenylalanine hydroxylase (PAH) (EC 1.14.16.1) is an enzyme that catalyzes the hydroxylation of the aromatic side-chain of phenylalanine to generate tyrosine.PAH is one of three members of the biopterin-dependent aromatic amino acid hydroxylases, a class of monooxygenase that uses tetrahydrobiopterin (BH 4, a pteridine cofactor) and a non-heme iron for catalysis.
Tyrosine hydroxylase or tyrosine 3-monooxygenase is the enzyme responsible for catalyzing the conversion of the amino acid L-tyrosine to L-3,4-dihydroxyphenylalanine (L-DOPA). [ 5 ] [ 6 ] It does so using molecular oxygen (O 2 ), as well as iron (Fe 2+ ) and tetrahydrobiopterin as cofactors .
4-Hydroxyphenylpyruvic acid (4-HPPA) is an intermediate in the metabolism of the amino acid phenylalanine. The aromatic side chain of phenylalanine is hydroxylated by the enzyme phenylalanine hydroxylase to form tyrosine. The conversion from tyrosine to 4-HPPA is in turn catalyzed by tyrosine aminotransferase. [2]
The conversion of Phe to Tyr is catalyzed by the enzyme phenylalanine hydroxylase, a monooxygenase. This enzyme catalyzes the reaction causing the addition of a hydroxyl group to the end of the 6-carbon aromatic ring of phenylalanine , such that it becomes tyrosine.
Hyperphenylalaninemia is a recessive hereditary metabolic disorder that is caused by the body's failure to convert phenylalanine to tyrosine as a result of the entire or partial absence of the enzyme phenylalanine hydroxylase. [3]
A conservative replacement (also called a conservative mutation or a conservative substitution or a homologous replacement) is an amino acid replacement in a protein that changes a given amino acid to a different amino acid with similar biochemical properties (e.g. charge, hydrophobicity and size).
Each one of these has its synthesis regulated from tyrosine, phenylalanine, and tryptophan, respectively. The rest of the enzymes in the common pathway (conversion of DAHP to chorismate) appear to be synthesized constitutively, except for shikimate kinase, which can be inhibited by shikimate through linear mixed-type inhibition.