| tyrosine 3-monooxygenase | <enzyme> An enzyme that catalyses the conversion of l-tyrosine, tetrahydrobiopterin, and oxygen to 3,4-dihydroxy-l-phenylalanine, dihydrobiopterin, and water. Chemical name: L-Tyrosine,tetrahydrobiopterin:oxygen oxidoreductase (3-hydroxylating) Registry number: EC 1.14.16.2 (12 Dec 1998) |
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| tyrosine aminotransferase | <enzyme> An enzyme that catalyses the reversible reaction of l-tyrosine and alpha-ketoglutarate producing p-hydroxyphenylpyruvate and l-glutamate; this enzyme catalyses a step in l-phenylalanine and l-tyrosine catabolism; a deficiency of this enzyme is associated with tyrosinaemia II. Synonym: tyrosine transaminase. (05 Mar 2000) |
| tyrosine decarboxylase | <enzyme> A pyridoxal-phosphate protein that catalyses the conversion of l-tyrosine to tyramine and carbon dioxide. The bacterial enzyme also acts on 3-hydroxytyrosine and, more slowly, on 3-hydroxyphenylalanine. Chemical name: L-Tyrosine carboxy-lyase Registry number: EC 4.1.1.25 (12 Dec 1998) |
| tyrosine hydroxylase | <enzyme> Enzyme required for the synthesis of the neurotransmitters noradrenaline and dopamine. (18 Nov 1997) |
| tyrosine iodinase | A postulated enzyme in the thyroid catalyzing iodination of tyrosine, a reaction important in the eventual biosynthesis of thyroxine. See: peroxidases. (05 Mar 2000) |
| tyrosine kinase | <enzyme> Kinases that phosphorylate protein tyrosine residues. These kinases play major roles in mitogenic signalling and can be divided into two subfamilies: receptor tyrosine kinases, that have an extracellular ligand binding domain, a single transmembrane domain and an intracellular tyrosine kinase domain and nonreceptor tyrosine kinases, which are soluble, cytoplasmic kinases. (18 Nov 1997) |
| tyrosine N-monooxygenase | <enzyme> Catalyses the n-hydroxylation of l-tyrosine to n-hydroxytyrosine Registry number: EC 1.14.13.41 Synonym: tyrosine n-hydroxylase, haemthiolate enzyme, cytochrome p450(tyr), cyp79 protein (26 Jun 1999) |
| tyrosine phenol-lyase | <enzyme> An enzyme that catalyses the cleavage of tyrosine to phenol, pyruvate, and ammonia. It is a pyridoxal phosphate protein. The enzyme also forms pyruvate from d-tyrosine, l-cysteine, s-methyl-l-cysteine, l-serine, and d-serine, although at a slower rate. Chemical name: L-Tyrosine phenol-lyase (deaminating) Registry number: EC 4.1.99.2 (12 Dec 1998) |
| tyrosine phosphorylation | <enzyme> Kinases that phosphorylate protein tyrosine residues. These kinases play major roles in mitogenic signalling and can be divided into two subfamilies: receptor tyrosine kinases, that have an extracellular ligand binding domain, a single transmembrane domain and an intracellular tyrosine kinase domain and nonreceptor tyrosine kinases, which are soluble, cytoplasmic kinases. (18 Nov 1997) |
| tyrosine transaminase | <enzyme> An enzyme that catalyses the conversion of l-tyrosine and 2-oxoglutarate to 4-hydroxyphenylpyruvate and l-glutamate. It is a pyridoxal-phosphate protein. L-phenylalanine can act instead of l-tyrosine. The mitochondrial enzyme may be identical with aspartate transaminase (ec 2.6.1.1.). Chemical name: L-Tyrosine:2-oxoglutarate aminotransferase Registry number: EC 2.6.1.5 (12 Dec 1998) |
| tyrosine-ester sulfotransferase | <enzyme> Also acts on phenols and organic hydroxylamines Registry number: EC 2.8.2.9 Synonym: arylsulfotransferase iv (26 Jun 1999) |
| tyrosine-repressible transaminase | <enzyme> From E coli; catalyses the amination of 2-ketoisocaproate to leucine; encoded by tyrb; a functional leuabcd operon is required for leucine synthesis by this enzyme Registry number: EC 2.6.1.- Synonym: transaminase d, tyrosine-2-ketoisocaproate aminotransferase (26 Jun 1999) |
| tyrosine-trna ligase | <enzyme> An enzyme that activates tyrosine with its specific transfer RNA. Chemical name: L-Tyrosine:tRNA-(Tyr) ligase (AMP-forming) Registry number: EC 6.1.1.1 (12 Dec 1998) |
| tyrosinosis | A very rare, possibly heritable disorder of tyrosine metabolism that may be caused by defective formation of p-hydroxyphenylpyruvic acid oxidase or of tyrosine transaminase; characterised by enhanced urinary excretion of p-hydroxyphenylpyruvic acid and of other tyrosyl metabolites upon ingestion of tyrosine or proteins containing that amino acid. Origin: tyrosine + G. -osis, condition (05 Mar 2000) |
| tyrosinuria | The excretion of tyrosine in the urine. Origin: tyrosine + G. Ouron, urine (05 Mar 2000) |