Activating Compound | Comment | Organism | Structure |
---|---|---|---|
additional information | the enzyme is activated on exposure to acid-pH, activation at pH 2.5 and at pH 4.0, reversal of the activation is possible at pH 7.0, the activation by SDS and acidic pH results in a localized conformational change that is anchored around the catalytic site of PPO that alters the microenvironment of an essential glutamic residue, concentration or on exposure to acid-pH, the enzymes possesses a core carboxylate essential to activity, this enhanced catalytic efficiency of PPO, overview | Lablab purpureus | |
SDS | severalfold activation at concentration below the critical micellar concentration of the enzyme, 15-20% activation at concentration below 0.3 mM, maximal activation at 1.25 mM, the activation by SDS and acidic pH results in a localized conformational change that is anchored around the catalytic site of PPO that alters the microenvironment of an essential glutamic residue | Lablab purpureus |
Inhibitors | Comment | Organism | Structure |
---|---|---|---|
1-ethyl-3-(3-dimethylaminopropyl) carbodiimide | irreversible inactivation, second-order rate constants | Lablab purpureus | |
glycine methyl ester hydrochloride | irreversible inactivation, second-order rate constants | Lablab purpureus | |
tropolone | pseudo first-order rate constants for inactivation | Lablab purpureus |
KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
additional information | - |
additional information | the enhancement of kcat upon activation is accompanied by a marked shift in the pH optimum for the oxidation of t-butyl catechol from 4.5 to 6.0, an increased sensitivity to tropolone, altered susceptibility to proteolytic degradation and decreased thermostability | Lablab purpureus |
Molecular Weight [Da] | Molecular Weight Maximum [Da] | Comment | Organism |
---|---|---|---|
12000 | - |
gel filtration | Lablab purpureus |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
additional information | Lablab purpureus | the enzyme is considered as defence oxidative enzyme, is vital the physiological defence strategy adapted by plants to insect herbivory and pathogen attack | ? | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Lablab purpureus | - |
field bean | - |
Purification (Comment) | Organism |
---|---|
native enzyme from seeds | Lablab purpureus |
Reaction | Comment | Organism | Reaction ID |
---|---|---|---|
2 catechol + O2 = 2 1,2-benzoquinone + 2 H2O | the enzymes possesses a core carboxylate essential to activity, this enhanced catalytic efficiency of PPO | Lablab purpureus |
Source Tissue | Comment | Organism | Textmining |
---|---|---|---|
seed | - |
Lablab purpureus | - |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
1-butylcatechol + O2 | - |
Lablab purpureus | ? | - |
? | |
additional information | the enzyme is considered as defence oxidative enzyme, is vital the physiological defence strategy adapted by plants to insect herbivory and pathogen attack | Lablab purpureus | ? | - |
? | |
additional information | the enzyme shows catecholase and cresolase activities, a type III copper protein that catalyses the O-hydroxylation of monophenols and oxidation of O-diphenols using molecular oxygen | Lablab purpureus | ? | - |
? |
Subunits | Comment | Organism |
---|---|---|
More | the Stokes radius of the native enzyme is found to increase from 49.1 to 75.9 A upon activation of the enzyme, neither SDS nor acid-pH activation brought about any change in the quaternary structure | Lablab purpureus |
tetramer | - |
Lablab purpureus |
Synonyms | Comment | Organism |
---|---|---|
catecholase | - |
Lablab purpureus |
cresolase | - |
Lablab purpureus |
polyphenol oxidase | - |
Lablab purpureus |
PPO | - |
Lablab purpureus |
Temperature Optimum [°C] | Temperature Optimum Maximum [°C] | Comment | Organism |
---|---|---|---|
25 | - |
assay at | Lablab purpureus |
Temperature Stability Minimum [°C] | Temperature Stability Maximum [°C] | Comment | Organism |
---|---|---|---|
additional information | - |
the activated enzyme is less thermostable than the native enzyme, overview | Lablab purpureus |
40 | - |
above, loss in activity | Lablab purpureus |
pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|
additional information | - |
the enhancement of kcat upon activation is accompanied by a marked shift in the pH optimum from pH 4.5 to pH 6.0 for the oxidation of t-butyl catechol from 4.5 to 6.0, an increased sensitivity to tropolone, altered susceptibility to proteolytic degradation and decreased thermostability, overview | Lablab purpureus |
4.5 | - |
native enzyme | Lablab purpureus |
6 | - |
activated enzyme | Lablab purpureus |
pH Minimum | pH Maximum | Comment | Organism |
---|---|---|---|
3 | 7 | - |
Lablab purpureus |