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Phenylalanine ball and stick model spinning. Phenylalanine (symbol Phe or F) [3] is an essential α-amino acid with the formula C 9 H 11 NO 2.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.
So, for convenience, sulfur-containing amino acids are sometimes considered a single pool of nutritionally equivalent amino acids as are the aromatic amino acid pair, phenylalanine and tyrosine. Likewise arginine , ornithine , and citrulline , which are interconvertible by the urea cycle , are considered a single group.
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.
In enzymology, a phenylalanine dehydrogenase (EC 1.4.1.20) is an enzyme that catalyzes the chemical reaction. L-phenylalanine + H 2 O + NAD + phenylpyruvate + NH 3 + NADH + H +. The 3 substrates of this enzyme are L-phenylalanine, H 2 O, and NAD +, whereas its 4 products are phenylpyruvate, NH 3, NADH, and H +.
Most common among natural products is the amino acid phenylalanine, which contains a phenyl group. A major product of the petrochemical industry is " BTX " consisting of benzene, toluene, and xylene - all of which are building blocks for phenyl compounds.
Tyrosine is semi-essential; therefore, it can be synthesized by the animal, but only from phenylalanine. Phenylketonuria, a genetic disorder that occurs as a result of the inability to breakdown phenylalanine, is due to a lack of the enzyme phenylalanine hydroxylase. A dietary lack of tryptophan can cause stunted skeletal development. [9]
Phenylalanine, tyrosine, and tryptophan, the aromatic amino acids, arise from chorismate. The first step, condensation of 3-deoxy-D-arabino-heptulosonic acid 7-phosphate (DAHP) from PEP/E4P, uses three isoenzymes AroF, AroG, and AroH. Each one of these has its synthesis regulated from tyrosine, phenylalanine, and tryptophan, respectively.
The experiments used mixtures with all 20 amino acids. For each individual experiment, 19 amino acids were "cold" (nonradioactive), and one was "hot" (radioactively tagged with 14 C so they could detect the tagged amino acid later). They varied the "hot" amino acid in each round of the experiment, seeking to determine which amino acids would be ...