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Literature summary for 1.14.20.5 extracted from

  • Han, X.J.; Wu, Y.F.; Gao, S.; Yu, H.N.; Xu, R.X.; Lou, H.X.; Cheng, A.X.
    Functional characterization of a Plagiochasma appendiculatum flavone synthase I showing flavanone 2-hydroxylase activity (2014), FEBS Lett., 588, 2307-2314 .
    View publication on PubMed

Cloned(Commentary)

Cloned (Comment) Organism
expression in Escherichia coli Plagiochasma appendiculatum

Protein Variants

Protein Variants Comment Organism
A120M when the purified recombinant mutant enzyme is incubated with naringenin as substrate, the ratio of 2-hydroxynaringenin to apigenin is reduced. The mutant enzyme is able to oxidize dihydrokaempferol to kaempferol with 162% of the catalytic activity relative to wild-type enzyme Plagiochasma appendiculatum
F146I when the purified recombinant mutant enzyme is incubated with naringenin as substrate, the ratio of 2-hydroxynaringenin to apigenin is reduced. The mutant enzyme is able to oxidize dihydrokaempferol to kaempferol with 86% of the catalytic activity relative to wild-type enzyme Plagiochasma appendiculatum
F146I/A120M the enzyme activity of the double mutant is reduced to a level of about 10% of the activity of the wild type enzyme and the only product generated is apigenin Plagiochasma appendiculatum
L311F when the purified recombinant mutant enzyme is incubated with naringenin as substrate, the ratio of 2-hydroxynaringenin to apigenin is reduced. The mutant enzyme is able to oxidize dihydrokaempferol to kaempferol with 355% of the catalytic activity relative to wild-type enzyme Plagiochasma appendiculatum
L311F/A120M the double mutant catalyzes the formation of 2-hydroxynaringenin and apigenin, although the ratio of these two compounds iss lower than that generated by the wild type enzyme Plagiochasma appendiculatum
L311F/F146I the double mutant catalyzes the formation of 2-hydroxynaringenin and apigenin, although the ratio of these two compounds iss lower than that generated by the wild type enzyme Plagiochasma appendiculatum
L311F/F146I/A120M the activity of the triple mutant falls to about 5% of the wild type enzyme Plagiochasma appendiculatum
L311F/F146I/Y240P inactive mutant Plagiochasma appendiculatum
L311F/F146I/Y240P/A120M inactive mutant Plagiochasma appendiculatum
L311F/Y240P the double mutant exhibits less flavone synthase activity than either the wild type or the Y240P single mutant enzymes Plagiochasma appendiculatum
Y240P the mutant enzyme converts naringenin to apigenin without producing any 2-hydroxynaringenin. The mutant has a higher affinity (lower Km) with naringenin than the wild type enzyme, but the catalytic efficiency of the mutant is lower than that of wild type enzyme. The mutant enzyme is able to oxidize dihydrokaempferol to kaempferol with 104% of the catalytic activity relative to wild-type enzyme Plagiochasma appendiculatum
Y240P/A120M the enzyme activity of the double mutant is reduced to a level of about 10% of the activity of the wild type enzyme and the only product generated is apigenin. The mutant enzyme is able to oxidize dihydrokaempferol to kaempferol with 175% of the catalytic activity relative to wild-type enzyme Plagiochasma appendiculatum
Y240P/F146I the enzyme activity of the double mutant is reduced to a level of about 10% of the activity of the wild type enzyme and the only product generated is apigenin Plagiochasma appendiculatum

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.0065
-
naringenin pH 7.0, 35°C, mutant enzyme Y240P Plagiochasma appendiculatum
0.0199
-
naringenin pH 7.0, 35°C, wild-type enzyme Plagiochasma appendiculatum

Organism

Organism UniProt Comment Textmining
Plagiochasma appendiculatum A0A076U8J8
-
-

Purification (Commentary)

Purification (Comment) Organism
-
Plagiochasma appendiculatum

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
dihydrokaempferol + 2-oxoglutarate + O2 the mutated enzymes L311F, Y240P, F146I, A120M and L311F–A120M are all able to oxidize dihydrokaempferol to kaempferol, with respective catalytic activities relative to the wild type level of 355%, 104%, 86%, 162% and 175%. L311F substitution increases the flavonol synthase activity Plagiochasma appendiculatum kaempferol + succinate + CO2 + H2O
-
?
additional information no activity with eriodictyol or dihydroquercetin Plagiochasma appendiculatum ?
-
?
naringenin + 2-oxoglutarate + O2 the enzyme catalyzes the conversion of naringenin to apigenin and 2-hydroxynaringenin. It is demonstrated that the enzyme is unable to catalyze the conversion of 2-hydroxynaringenin to apigenin. It is also confirmed that 2-hydroxynaringenin cannot be an intermediate product in the conversion of naringenin to apigenin, leaving the mechanism of conversion unknown Plagiochasma appendiculatum apigenin + 2-hydroxynaringenin + succinate + CO2 + H2O
-
?

Subunits

Subunits Comment Organism
? x * 61000, SDS-PAGE Plagiochasma appendiculatum

Synonyms

Synonyms Comment Organism
flavone synthase I
-
Plagiochasma appendiculatum
FNS I
-
Plagiochasma appendiculatum

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
35
-
-
Plagiochasma appendiculatum

Turnover Number [1/s]

Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
0.002
-
naringenin pH 7.0, 35°C, mutant enzyme Y240P Plagiochasma appendiculatum
0.027
-
naringenin pH 7.0, 35°C, wild-type enzyme Plagiochasma appendiculatum

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
7
-
-
Plagiochasma appendiculatum

pI Value

Organism Comment pI Value Maximum pI Value
Plagiochasma appendiculatum calculated from sequence
-
6.42

General Information

General Information Comment Organism
physiological function involved in flavonoid pathway Plagiochasma appendiculatum

kcat/KM [mM/s]

kcat/KM Value [1/mMs-1] kcat/KM Value Maximum [1/mMs-1] Substrate Comment Organism Structure
0.305
-
naringenin pH 7.0, 35°C, mutant enzyme Y240P Plagiochasma appendiculatum
1.372
-
naringenin pH 7.0, 35°C, wild-type enzyme Plagiochasma appendiculatum