Phenylalanine
Phenylalanine Hydroxylase
An enzyme of the oxidoreductase class that catalyzes the formation of L-TYROSINE, dihydrobiopterin, and water from L-PHENYLALANINE, tetrahydrobiopterin, and oxygen. Deficiency of this enzyme may cause PHENYLKETONURIAS and PHENYLKETONURIA, MATERNAL. EC 1.14.16.1.
Phenylalanine Ammonia-Lyase
Phenylketonurias
A group of autosomal recessive disorders marked by a deficiency of the hepatic enzyme PHENYLALANINE HYDROXYLASE or less frequently by reduced activity of DIHYDROPTERIDINE REDUCTASE (i.e., atypical phenylketonuria). Classical phenylketonuria is caused by a severe deficiency of phenylalanine hydroxylase and presents in infancy with developmental delay; SEIZURES; skin HYPOPIGMENTATION; ECZEMA; and demyelination in the central nervous system. (From Adams et al., Principles of Neurology, 6th ed, p952).
Phenylpyruvic Acids
Tyrosine
Amino Acids
Ammonia-Lyases
Prephenate Dehydratase
An enzyme that catalyzes the conversion of prephenate to phenylpyruvate with the elimination of water and carbon dioxide. In the enteric bacteria this enzyme also possesses chorismate mutase activity, thereby catalyzing the first two steps in the biosynthesis of phenylalanine. EC 4.2.1.51.
Tryptophan
An essential amino acid that is necessary for normal growth in infants and for NITROGEN balance in adults. It is a precursor of INDOLE ALKALOIDS in plants. It is a precursor of SEROTONIN (hence its use as an antidepressant and sleep aid). It can be a precursor to NIACIN, albeit inefficiently, in mammals.
Molecular Sequence Data
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
Amino Acid Sequence
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
Phenylalanine-tRNA Ligase
Phenylketonuria, Maternal
A condition occurring in untreated or partially treated females with PHENYLKETONURIA when they become pregnant. This may result in damages to the FETUS, including MICROCEPHALY; MENTAL RETARDATION; congenital heart disease; FETAL GROWTH RETARDATION; and CRANIOFACIAL ABNORMALITIES. (From Am J Med Genet 1997 Mar 3;69(1):89-95)
Fenclonine
A selective and irreversible inhibitor of tryptophan hydroxylase, a rate-limiting enzyme in the biosynthesis of serotonin (5-HYDROXYTRYPTAMINE). Fenclonine acts pharmacologically to deplete endogenous levels of serotonin.
Chorismate Mutase
Mutagenesis, Site-Directed
Mutation
Amino Acids, Essential
Carbon Isotopes
Binding Sites
Hydroxylation
Pteridines
3-Deoxy-7-Phosphoheptulonate Synthase
An enzyme that catalyzes the formation of 7-phospho-2-keto-3-deoxy-D-arabinoheptonate from phosphoenolpyruvate and D-erythrose-4-phosphate. It is one of the first enzymes in the biosynthesis of TYROSINE and PHENYLALANINE. This enzyme was formerly listed as EC 4.1.2.15.
Rhodotorula
Nutritional Requirements
Liver
Hydro-Lyases
Deuterium
Base Sequence
Escherichia coli
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
Isoleucine
An essential branched-chain aliphatic amino acid found in many proteins. It is an isomer of LEUCINE. It is important in hemoglobin synthesis and regulation of blood sugar and energy levels.
Models, Molecular
Phenylacetates
Derivatives of phenylacetic acid. Included under this heading are a variety of acid forms, salts, esters, and amides that contain the benzeneacetic acid structure. Note that this class of compounds should not be confused with derivatives of phenyl acetate, which contain the PHENOL ester of ACETIC ACID.
Structure-Activity Relationship
Amino Acid Substitution
The naturally occurring or experimentally induced replacement of one or more AMINO ACIDS in a protein with another. If a functionally equivalent amino acid is substituted, the protein may retain wild-type activity. Substitution may also diminish, enhance, or eliminate protein function. Experimentally induced substitution is often used to study enzyme activities and binding site properties.
Alanine
Muscle Proteins
Protein Conformation
The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).
RNA, Transfer, Phe
Food, Formulated
Valine
Substrate Specificity
Leucine Dehydrogenase
An octameric enzyme belonging to the superfamily of amino acid dehydrogenases. Leucine dehydrogenase catalyzes the reversible oxidative deamination of L-LEUCINE, to 4-methyl-2-oxopentanoate (2-ketoisocaproate) and AMMONIA, with the corresponding reduction of the cofactor NAD+.
Chromobacterium
Protein Binding
Aldehyde-Lyases
Oxidation-Reduction
A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).
Protein Biosynthesis
The biosynthesis of PEPTIDES and PROTEINS on RIBOSOMES, directed by MESSENGER RNA, via TRANSFER RNA that is charged with standard proteinogenic AMINO ACIDS.
Dietary Proteins
Proteins obtained from foods. They are the main source of the ESSENTIAL AMINO ACIDS.
RNA, Transfer
The small RNA molecules, 73-80 nucleotides long, that function during translation (TRANSLATION, GENETIC) to align AMINO ACIDS at the RIBOSOMES in a sequence determined by the mRNA (RNA, MESSENGER). There are about 30 different transfer RNAs. Each recognizes a specific CODON set on the mRNA through its own ANTICODON and as aminoacyl tRNAs (RNA, TRANSFER, AMINO ACYL), each carries a specific amino acid to the ribosome to add to the elongating peptide chains.
Shikimic Acid
RNA, Transfer, Amino Acyl
Intermediates in protein biosynthesis. The compounds are formed from amino acids, ATP and transfer RNA, a reaction catalyzed by aminoacyl tRNA synthetase. They are key compounds in the genetic translation process.
Tetroses
Phosphorylation
Hydrogen-Ion Concentration
Dihydropteridine Reductase
Fluorine
Glycine
Protein Structure, Tertiary
The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.
Catalysis
Mitosporic Fungi
Protein Hydrolysates
Protein hydrolysates are defined as complex mixtures of peptides produced by the enzymatic or chemical breakdown of whole proteins, which can vary in their degree of hydrolysis and molecular weight, and are used in various medical and nutritional applications due to their improved digestibility and bioavailability compared to intact proteins.
Cloning, Molecular
Cinnamates
Point Mutation
A mutation caused by the substitution of one nucleotide for another. This results in the DNA molecule having a change in a single base pair.
Transaminases
Sequence Homology, Amino Acid
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
Spectrophotometry, Ultraviolet
Enzyme Activation
Tyrosine Transaminase
An enzyme that catalyzes the conversion of L-TYROSINE and 2-oxoglutarate to 4-hydroxyphenylpyruvate and L-GLUTAMATE. It is a pyridoxal-phosphate protein. L-PHENYLALANINE is hydroxylated to L-tyrosine. The mitochondrial enzyme may be identical with ASPARTATE AMINOTRANSFERASES (EC 2.6.1.1.). Deficiency of this enzyme may cause type II Tyrosinemia (see TYROSINEMIAS). EC 2.6.1.5.
Homogentisate 1,2-Dioxygenase
A mononuclear Fe(II)-dependent oxygenase, this enzyme catalyzes the conversion of homogentisate to 4-maleylacetoacetate, the third step in the pathway for the catabolism of TYROSINE. Deficiency in the enzyme causes ALKAPTONURIA, an autosomal recessive disorder, characterized by homogentisic aciduria, OCHRONOSIS and ARTHRITIS. This enzyme was formerly characterized as EC 1.13.1.5 and EC 1.99.2.5.
Amino Acyl-tRNA Synthetases
A subclass of enzymes that aminoacylate AMINO ACID-SPECIFIC TRANSFER RNA with their corresponding AMINO ACIDS.
Electrophoresis, Polyacrylamide Gel
Cyclohexanecarboxylic Acids
Magnetic Resonance Spectroscopy
Plants
Multicellular, eukaryotic life forms of kingdom Plantae (sensu lato), comprising the VIRIDIPLANTAE; RHODOPHYTA; and GLAUCOPHYTA; all of which acquired chloroplasts by direct endosymbiosis of CYANOBACTERIA. They are characterized by a mainly photosynthetic mode of nutrition; essentially unlimited growth at localized regions of cell divisions (MERISTEMS); cellulose within cells providing rigidity; the absence of organs of locomotion; absence of nervous and sensory systems; and an alternation of haploid and diploid generations.
Stereoisomerism
Chromatography, High Pressure Liquid
Radioactive Tracers
Radioactive substances added in minute amounts to the reacting elements or compounds in a chemical process and traced through the process by appropriate detection methods, e.g., Geiger counter. Compounds containing tracers are often said to be tagged or labeled. (Hawley's Condensed Chemical Dictionary, 12th ed)
Tryptophan Hydroxylase
An enzyme that catalyzes the hydroxylation of TRYPTOPHAN to 5-HYDROXYTRYPTOPHAN in the presence of NADPH and molecular oxygen. It is important in the biosynthesis of SEROTONIN.
Sequence Alignment
The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.