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Literature summary for 1.14.18.1 extracted from

  • Kumar, V.B.; Mohan, T.C.; Murugan, K.
    Purification and kinetic characterization of polyphenol oxidase from Barbados cherry (Malpighia glabra L.) (2008), Food Chem., 110, 328-333.
    View publication on PubMed

Application

Application Comment Organism
food industry browning in fruits and vegetables is recognized as a serious problem in the food industry. Further studies are warranted to understand the PPO inhibitor in relation to the browning reaction of fruit during storage and processing Malpighia glabra

Inhibitors

Inhibitors Comment Organism Structure
2-mercaptoethanol evaluated for effectiveness as an inhibitor of PPO activity, using catechol as the substrate Malpighia glabra
CaCl2 evaluated for effectiveness as an inhibitor of PPO activity, using catechol as the substrate Malpighia glabra
EDTA evaluated for effectiveness as an inhibitor of PPO activity, using catechol as the substrate Malpighia glabra
L-ascorbate significantly inhibits PPO activity, evaluated for effectiveness as an inhibitor of PPO activity, using catechol as the substrate Malpighia glabra
L-cysteine significantly inhibits PPO activity, evaluated for effectiveness as an inhibitor of PPO activity, using catechol as the substrate Malpighia glabra
Sodium azide evaluated for effectiveness as an inhibitor of PPO activity, using catechol as the substrate Malpighia glabra
Sodium diethyl dithiocarbamate SDDC, significantly inhibits PPO activity, evaluated for effectiveness as an inhibitor of PPO activity, using catechol as the substrate. Inhibitors such as sodium diethyl dithiocarbamate and thiourea, which combine with the copper moiety in the enzyme, are generally potent inhibitors of PPO. The inhibitors are copper-chelating agents and they suppress browning activities in which copper is directly involved in the oxidation of phenolic compounds Malpighia glabra
Sodium metabisulfite evaluated for effectiveness as an inhibitor of PPO activity, using catechol as the substrate Malpighia glabra
Thiourea evaluated for effectiveness as an inhibitor of PPO activity, using catechol as the substrate. Inhibitors such as sodium diethyl dithiocarbamate and thiourea, which combine with the copper moiety in the enzyme, are generally potent inhibitors of PPO. The inhibitors are copper-chelating agents and they suppress browning activities in which copper is directly involved in the oxidation of phenolic compounds Malpighia glabra

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
1.24
-
pyrogallol
-
Malpighia glabra
3.6
-
caffeic acid
-
Malpighia glabra
4.1
-
L-Dopa
-
Malpighia glabra
5.2
-
catechol
-
Malpighia glabra
6.9
-
4-methylcatechol
-
Malpighia glabra

Metals/Ions

Metals/Ions Comment Organism Structure
copper inhibitors such as sodium diethyl dithiocarbamate and thiourea, which combine with the copper moiety in the enzyme, are generally potent inhibitors of PPO. The inhibitors are copper-chelating agents and they suppress browning activities in which copper is directly involved in the oxidation of phenolic compounds Malpighia glabra

Molecular Weight [Da]

Molecular Weight [Da] Molecular Weight Maximum [Da] Comment Organism
38000
-
1 * 52000 + 1 * 38000, the electrophoretic pattern of cherry PPO in SDS-PAGE reveals two dominant bands with molecular masses of 52 and 38 kDa Malpighia glabra
52000
-
1 * 52000 + 1 * 38000, the electrophoretic pattern of cherry PPO in SDS-PAGE reveals two dominant bands with molecular masses of 52 and 38 kDa Malpighia glabra

Organism

Organism UniProt Comment Textmining
Malpighia glabra
-
the Barbados cherry (Malpighia glabra L.) has a very short shelf life under ambient conditions due to skin colour loss and quality deterioration during storage
-

Purification (Commentary)

Purification (Comment) Organism
extracted and purified through ammonium sulfate precipitation, gel filtration, and affinity chromatography Malpighia glabra

Specific Activity [micromol/min/mg]

Specific Activity Minimum [µmol/min/mg] Specific Activity Maximum [µmol/min/mg] Comment Organism
additional information
-
40192 U/mg, phenyl sepharose, purification profile of Barbados cherry PPO. One Unit of enzyme activity is defined as the amount of enzyme that caused an increase in absorbance of 0.001 min-1 Malpighia glabra

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
4-methylcatechol + 1/2 O2 efficient diphenolic substrates for cherry PPO Malpighia glabra 4-methyl-1,2-benzoquinone + H2O
-
?
caffeic acid + 1/2 O2
-
Malpighia glabra caffeoyl quinone + H2O
-
?
catechol + 1/2 O2 efficient diphenolic substrates for cherry PPO Malpighia glabra 1,2-benzoquinone + H2O
-
?
D-tyrosine + O2 + AH2
-
Malpighia glabra L-3,4-dihydroxyphenylalanine + H2O + A
-
?
ferulic acid + O2 + AH2
-
Malpighia glabra (2E)-3-(3,4-dihydroxy-5-methoxyphenyl)prop-2-enoic acid + H2O + A
-
?
L-dopa + 1/2 O2
-
Malpighia glabra L-dopaquinone + H2O
-
?
additional information substrate-binding site of cherry PPO has a high affinity for small o-diphenols, such as catechol, 4-methylcatechol or L-dopa, and less affinity for the larger o-diphenols, caffeic acid, and triphenol-pyrogallol Malpighia glabra ?
-
?
pyrogallol + 1/2 O2
-
Malpighia glabra ?
-
?

Subunits

Subunits Comment Organism
heterodimer 1 * 52000 + 1 * 38000, the electrophoretic pattern of cherry PPO in SDS-PAGE reveals two dominant bands with molecular masses of 52 and 38 kDa Malpighia glabra

Synonyms

Synonyms Comment Organism
polyphenol oxidase
-
Malpighia glabra
PPO
-
Malpighia glabra

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
24
-
optimum temperature of cherry PPO, with caffeic acid as substrate Malpighia glabra
25
-
optimum temperature of cherry PPO, with ferulic acid as substrate Malpighia glabra
30
-
optimum temperature of cherry PPO, with pyrogallol as substrate Malpighia glabra
36
-
optimum temperature of cherry PPO, with 4-methylcatechol as substrate Malpighia glabra
40
-
optimum temperature of cherry PPO, with catechol as substrate Malpighia glabra
41
-
optimum temperature of cherry PPO, with L-dopa as substrate Malpighia glabra
47
-
optimum temperature of cherry PPO, with D-tyrosine as substrate Malpighia glabra

Temperature Stability [°C]

Temperature Stability Minimum [°C] Temperature Stability Maximum [°C] Comment Organism
additional information
-
enzyme is relatively stable at 60°C, with 55% loss of activity, unstable at temperatures above 75°C. The enzyme is incubated at different temperatures (45-85°C) for 30 min and, after cooling, the residual enzyme activity is measured Malpighia glabra

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
5.2
-
optimum pH of cherry PPO, with D-tyrosine as substrate Malpighia glabra
5.4
-
optimum pH of cherry PPO, with caffeic acid as substrate Malpighia glabra
5.6
-
optimum pH of cherry PPO, with ferulic acid as substrate Malpighia glabra
6.6
-
optimum pH of cherry PPO, with L-dopa as substrate Malpighia glabra
7
-
optimum pH of cherry PPO, with 4-methylcatechol as substrate Malpighia glabra
7
-
optimum pH of cherry PPO, with catechol as substrate Malpighia glabra
8
-
optimum pH of cherry PPO, with pyrogallol as substrate Malpighia glabra