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Literature summary for 1.14.18.1 extracted from

  • Bijelic, A.; Pretzler, M.; Molitor, C.; Zekiri, F.; Rompel, A.
    The structure of a plant tyrosinase from walnut leaves reveals the importance of substrate-guiding residues for enzymatic specificity (2015), Angew. Chem. Int. Ed. Engl., 54, 14677-14680 .
    View publication on PubMedView publication on EuropePMC
Search for more literature for 1.14.18.1

Crystallization (Commentary)

Crystallization (Comment) Organism
purified enzyme in its resting met form with a Cu-Cu distance of 4.0 A, X-ray diffraction structure determination and analysis Juglans regia

Metals/Ions

Metals/Ions Comment Organism Structure
Cu2+ a copper-containing enzyme. During the catalytic cycle, the dinuclear copper center passes through three different oxidation states. In the resting met form, the copper atoms (CuII) are bridged by a hydroxide ion or water molecule. The deoxy form represents the reduced (CuI) state, which is converted into the reactive oxy form upon oxygen binding. In the crystal structure, CuA exhibits an intermediate geometry between a distorted tetrahedron and a trigonal bipyramid with one unoccupied coordination site, whereas CuB exhibits an almost perfect tetrahedral geometry with the solvent molecule in apical position Juglans regia

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
additional information Juglans regia tyrosinases and catechol oxidases (EC 1.10.3.1) are members of the class of type III copper enzymes. While tyrosinases accept both mono- and o-diphenols as substrates, only the latter substrate is converted by catechol oxidases. The crystal structure reveals that the distinction between mono- and diphenolase activity does not depend on the degree of restriction of the active site, and thus a more important role for amino acid residues located at the entrance to and in the second shell of the active site is proposed ?
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Organism

Organism UniProt Comment Textmining
Juglans regia
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Reaction

Reaction Comment Organism Reaction ID
2 L-dopa + O2 = 2 dopaquinone + 2 H2O structure-function relationship analysis and reaction mechanism, overview. The crystal structure reveals that the distinction between mono- and diphenolase activity does not depend on the degree of restriction of the active site, and thus a more important role for amino acid residues located at the entrance to and in the second shell of the active site is proposed Juglans regia
a

Source Tissue

Source Tissue Comment Organism Textmining
leaf
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 Juglans regia
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Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
additional information tyrosinases and catechol oxidases (EC 1.10.3.1) are members of the class of type III copper enzymes. While tyrosinases accept both mono- and o-diphenols as substrates, only the latter substrate is converted by catechol oxidases. The crystal structure reveals that the distinction between mono- and diphenolase activity does not depend on the degree of restriction of the active site, and thus a more important role for amino acid residues located at the entrance to and in the second shell of the active site is proposed Juglans regia ?
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 ?

Synonyms

Synonyms Comment Organism
jrTYR
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 Juglans regia

General Information

General Information Comment Organism
evolution tyrosinases and catechol oxidases (EC 1.10.3.1) are members of the class of type III copper enzymes. While tyrosinases accept both mono- and o-diphenols as substrates, only the latter substrate is converted by catechol oxidases. The distinction between mono- and diphenolase activity does not depend on the degree of restriction of the active site, and thus a more important role for amino acid residues located at the entrance to and in the second shell of the active site is proposed Juglans regia
malfunction silencing of walnut tyrosinase (jrTYR) induces a lesion mimic phenotype in walnut leaves, presumably owing to tyramine-mediated cell death Juglans regia
additional information the enzyme shows monophenolase/diphenolase specificity, structure-function relationship analysis, overview. Enzyme jrTYR contains the well-conserved tyrosinase CXXC motif (C88 A-Y-C91), which has been reported to be crucial for copper uptake. Active site structure analysis Juglans regia
physiological function tyrosinase catalyzes the reactions that provide the starting material for melanin biosynthesis, namely the ortho-hydroxylation of monophenols to o-diphenols (monophenolase activity, EC 1.14.18.1) and the subsequent oxidation of o-diphenols to the corresponding o-quinones (diphenolase activity, EC 1.10.3.1), which are both coupled to the reduction of molecular oxygen to water. During the catalytic cycle, the dinuclear copper center passes through three different oxidation states. In the resting met form, the copper atoms (CuII) are bridged by a hydroxide ion or water molecule. The deoxy form represents the reduced (CuI) state, which is converted into the reactive oxy form upon oxygen binding Juglans regia