ExplorEnz: EC 4.1.99.2

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4.1.99.2

Accepted name:

tyrosine phenol-lyase

Reaction:

L-tyrosine + H₂O = phenol + pyruvate + NH₃ (overall reaction)
(1a) L-tyrosine = phenol + 2-aminoprop-2-enoate
(1b) 2-aminoprop-2-enoate = 2-iminopropanoate (spontaneous)
(1c) 2-iminopropanoate + H₂O = pyruvate + NH₃ (spontaneous)

Other name(s):

β-tyrosinase; L-tyrosine phenol-lyase (deaminating)

Systematic name:

L-tyrosine phenol-lyase (deaminating; pyruvate-forming)

Comments:

A pyridoxal-phosphate protein. The enzyme cleaves a carbon-carbon bond, releasing phenol and an unstable enamine product that tautomerizes to an imine form, which undergoes a hydrolytic deamination to form pyruvate and ammonia. The latter reaction, which can occur spontaneously, can also be catalysed by EC 3.5.99.10, 2-iminobutanoate/2-iminopropanoate deaminase. The enzyme also slowly catalyses similar reactions with D-tyrosine, S-methyl-L-cysteine, L-cysteine, L-serine and D-serine.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 9059-31-8

References:

1.	Kumagai, H., Yamada, H., Matsui, H., Ohkishi, H. and Ogata, K. Tyrosine phenol lyase. I. Purification, crystallization, and properties. J. Biol. Chem. 245 (1970) 1767–1772. [PMID: 4908868]
2.	Kumagai, H., Yamada, H., Matsui, H., Ohkishi, H. and Ogata, K. Tyrosine phenol lyase. II. Cofactor requirements. J. Biol. Chem. 245 (1970) 1773–1777. [PMID: 4908869]

[EC 4.1.99.2 created 1972]