Inhibitors | Comment | Organism | Structure |
---|---|---|---|
ascorbic acid | in descending order of inhibition potency: p-hydroxybenzoic acid > glutathione = ascorbic acid > L-cysteine > EDTA > citric acid | Lactuca sativa | |
Citric acid | in descending order of inhibition potency: p-hydroxybenzoic acid > glutathione = ascorbic acid > L-cysteine > EDTA > citric acid | Lactuca sativa | |
EDTA | in descending order of inhibition potency: p-hydroxybenzoic acid > glutathione = ascorbic acid > L-cysteine > EDTA > citric acid | Lactuca sativa | |
glutathione | in descending order of inhibition potency: p-hydroxybenzoic acid > glutathione = ascorbic acid > L-cysteine > EDTA > citric acid | Lactuca sativa | |
L-cysteine | in descending order of inhibition potency: p-hydroxybenzoic acid > glutathione = ascorbic acid > L-cysteine > EDTA > citric acid | Lactuca sativa | |
p-hydroxybenzoic acid | in descending order of inhibition potency: p-hydroxybenzoic acid > glutathione = ascorbic acid > L-cysteine > EDTA > citric acid | Lactuca sativa |
KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
1 | - |
4-methylcatechol | - |
Lactuca sativa | |
3.2 | - |
catechol | - |
Lactuca sativa |
Molecular Weight [Da] | Molecular Weight Maximum [Da] | Comment | Organism |
---|---|---|---|
60000 | - |
SDS-PAGE | Lactuca sativa |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Lactuca sativa | - |
var. capitata L. | - |
Purification (Comment) | Organism |
---|---|
partial purification | Lactuca sativa |
Specific Activity Minimum [µmol/min/mg] | Specific Activity Maximum [µmol/min/mg] | Comment | Organism |
---|---|---|---|
additional information | - |
26285 U/mg. An increase in absorbance of 0.001 min-1 is taken as one Unit of enzyme activity. G-100, purification step | Lactuca sativa |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
4-methylcatechol + 1/2 O2 | PPO from butter lettuce shows a higher affinity to 4-methylcatechol than to catechol | Lactuca sativa | 4-methyl-1,2-benzoquinone + H2O | - |
? | |
caffeic acid + 1/2 O2 | - |
Lactuca sativa | caffeoyl quinone + H2O | - |
? | |
catechol + 1/2 O2 | PPO from butter lettuce shows a higher affinity to 4-methylcatechol than to catechol | Lactuca sativa | o-benzoquinone + H2O | - |
? | |
chlorogenic acid + 1/2 O2 | - |
Lactuca sativa | chlorogenoquinone + H2O | - |
? | |
ferulic acid + O2 + AH2 | - |
Lactuca sativa | (2E)-3-(3,4-dihydroxy-5-methoxyphenyl)prop-2-enoic acid + H2O + A | - |
? | |
additional information | no activity with vanillin and tyrosine as a substrate | Lactuca sativa | ? | - |
? |
Synonyms | Comment | Organism |
---|---|---|
polyphenol oxidase | - |
Lactuca sativa |
PPO | enzyme catalyses two distinct reactions: the o-hydroxylation of monophenols to o-diphenols (acts like cresolase) (E.C. 1.14.18.1) and the oxidation of o-diphenols to o-quinones (acts like catecholase) (E.C. 1.10.3.2) | Lactuca sativa |
Temperature Optimum [°C] | Temperature Optimum Maximum [°C] | Comment | Organism |
---|---|---|---|
35 | - |
- |
Lactuca sativa |
Temperature Stability Minimum [°C] | Temperature Stability Maximum [°C] | Comment | Organism |
---|---|---|---|
30 | 40 | enzyme is relatively stable at 30°C and 40°C. Thermal stability of partially purified PPO is investigated at pH 6.8 at various constant of temperatures from 25°C to 70°C using incubation time from 10 to 60 min. Residual PPO activity is then measured using 10 mM catechol substrate | Lactuca sativa |
pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|
5.5 | - |
catechol as a substrate | Lactuca sativa |
6.8 | - |
4-methylcatechol as a substrate | Lactuca sativa |
pH Stability | pH Stability Maximum | Comment | Organism |
---|---|---|---|
additional information | - |
PPO activity, as a function of pH, is determined under standard conditions using various buffers in the pH buffering range 2.0-12.0 | Lactuca sativa |
IC50 Value | IC50 Value Maximum | Comment | Organism | Inhibitor | Structure |
---|---|---|---|---|---|
4.54 | - |
- |
Lactuca sativa | p-hydroxybenzoic acid | |
4.61 | - |
- |
Lactuca sativa | ascorbic acid | |
4.7 | - |
- |
Lactuca sativa | glutathione | |
10.39 | - |
- |
Lactuca sativa | L-cysteine | |
26.4 | - |
- |
Lactuca sativa | EDTA | |
62.91 | - |
- |
Lactuca sativa | Citric acid |