Any feedback?
Please rate this page
(literature.php)
(0/150)

BRENDA support

Literature summary for 1.10.3.1 extracted from

  • Dirks-Hofmeister, M.E.; Inlow, J.K.; Moerschbacher, B.M.
    Site-directed mutagenesis of a tetrameric dandelion polyphenol oxidase (PPO-6) reveals the site of subunit interaction (2012), Plant Mol. Biol., 80, 203-217.
    View publication on PubMed

Cloned(Commentary)

Cloned (Comment) Organism
gene ppo-6, expression of N-terminally Strep2-tagged isozyme PPO-6 in Escherichia coli strain Rosetta2(DE3) pLysSRARE2 Taraxacum officinale

Protein Variants

Protein Variants Comment Organism
C197S site-directed mutagenesis of isozyme PPO-6, the C197S-mutein still forms a tetrameric structure but shows impaired enzymatic efficiency and cooperativity and a reduction in stability compared to the wild-type enzyme Taraxacum officinale

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
additional information
-
additional information wild-type isozyme PPO-6 displays a low degree in cooperativity in catalysis. Cooperativity of the C197S mutein is significantly decreased at pH 3.5, under SDS activation at pH 5.0 the degree of cooperativity of the C197S mutein is similar to that of the PPO-6 wild-type enzyme Taraxacum officinale

Metals/Ions

Metals/Ions Comment Organism Structure
Cu2+ a type 3 copper protein Taraxacum officinale

Molecular Weight [Da]

Molecular Weight [Da] Molecular Weight Maximum [Da] Comment Organism
60000
-
2 * 60000, recombinant mutant C197S mutein-tagged isozyme PPO-6, SDS-PAGE Taraxacum officinale
60000
-
4 * 60000, recombinant wild-type Strep2-tagged isozyme PPO-6, SDS-PAGE Taraxacum officinale
120000
-
recombinant mutant C197S mutein-tagged isozyme PPO-6, native PAGE Taraxacum officinale
250000
-
recombinant Strep2-tagged isozyme PPO-6, native PAGE Taraxacum officinale

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
2 o-diphenol + O2 Taraxacum officinale
-
2 o-quinone + 2 H2O
-
?
additional information Taraxacum officinale the enzyme catalyzes the oxidation of ortho-diphenols to the corresponding quinones ?
-
?

Organism

Organism UniProt Comment Textmining
Taraxacum officinale I7HUF2 PPO-6; gene ppo-6
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
2 4-methylcatechol + O2
-
Taraxacum officinale 2 4-methyl-1,2-benzoquinone + 2 H2O
-
?
2 o-diphenol + O2
-
Taraxacum officinale 2 o-quinone + 2 H2O
-
?
2 o-diphenol + O2 the reaction depends on molecular oxygen, which is reduced by the copper-containing catalytic domain of the enzyme Taraxacum officinale 2 o-quinone + 2 H2O
-
?
additional information the enzyme catalyzes the oxidation of ortho-diphenols to the corresponding quinones Taraxacum officinale ?
-
?

Subunits

Subunits Comment Organism
dimer 2 * 60000, recombinant mutant C197S mutein-tagged isozyme PPO-6, SDS-PAGE Taraxacum officinale
More isozyme PPO-6 is a tetramer, the surface-exposed Cys197 residue stabilizes the tetramer via a disulfide linkage Taraxacum officinale
tetramer 4 * 60000, recombinant wild-type Strep2-tagged isozyme PPO-6, SDS-PAGE Taraxacum officinale

Synonyms

Synonyms Comment Organism
PPO-6
-
Taraxacum officinale

General Information

General Information Comment Organism
additional information modeling of the three-dimensional structure of the PPO-6 tyrosinase domain Taraxacum officinale