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Literature summary for 1.10.3.1 extracted from

  • Yamamoto, K.; Yoshitama, K.; Teramoto, S.
    Purification and characterization of polyphenol oxidase from callus cultures of Portulaca grandiflora (2002), Plant Biotechnol., 19, 95-101.
No PubMed abstract available

Inhibitors

Inhibitors Comment Organism Structure
2-hydroxy-2,4,6-cycloheptatrien-1-one 1 mM, complete inhibition of isoenzymes Ia, Ib and II Portulaca grandiflora
4-chloromercuribenzoate 1 mM, 96, 94 and 95% inhibition of isoenzymes Ia, Ib and II respectively Portulaca grandiflora
ascorbic acid
-
Portulaca grandiflora
Fe2+ 88%, 68% and 80% inhibition of isoenzymes Ia, Ib, and II, respectively Portulaca grandiflora
glutathione 1 mM, 98%, 95% and 96% inhibition of isoenzymes Ia, Ib, and II, respectively Portulaca grandiflora
iodoacetate 1 mM; 1 mM: 46%, 39% and 31% inhibition of isoenzymes Ia, Ib, and II, respectively Portulaca grandiflora
isoascorbic acid 1 mM, complete inhibition of isoenzymes Ia, Ib and II Portulaca grandiflora
kojic acid 1 mM complete inhibition of isoenzymes Ia, Ib and II Portulaca grandiflora
mimosine 1 mM, 88%, 79% and 82% inhibition of isoenzymes Ia, Ib, and II, respectively Portulaca grandiflora
additional information not inhibited by 2,2'-dipyridyl, 1,10-phenanthroline and EDTA Portulaca grandiflora

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
2
-
L-Dopa isoenzyme Ia Portulaca grandiflora
2.2
-
L-Dopa isoenzyme Ib Portulaca grandiflora
3.5
-
L-Dopa isoenzyme II Portulaca grandiflora

Molecular Weight [Da]

Molecular Weight [Da] Molecular Weight Maximum [Da] Comment Organism
25000
-
1 * 27000 + 1 * 25000, isoenzyme II, SDS-PAGE Portulaca grandiflora
27000
-
1 * 27000 + 1 * 25000, isoenzyme II, SDS-PAGE Portulaca grandiflora
53000
-
isoenzyme II, gel filtration Portulaca grandiflora
65000
-
isoenzymes Ia and Ib, gel filtration Portulaca grandiflora
66000
-
1 * 66000, isoenzyme Ia, SDS-PAGE Portulaca grandiflora

Organism

Organism UniProt Comment Textmining
Portulaca grandiflora
-
isoenzymes Ia, Ib and II
-

Purification (Commentary)

Purification (Comment) Organism
isoenzymes Ia, Ib and II ammonium sulfate, DEAE-cellulose, Sephacryl S-200, hydroxyapatite, Mono Q Portulaca grandiflora

Source Tissue

Source Tissue Comment Organism Textmining
callus cell culture Portulaca grandiflora
-

Specific Activity [micromol/min/mg]

Specific Activity Minimum [µmol/min/mg] Specific Activity Maximum [µmol/min/mg] Comment Organism
additional information
-
isoenzyme Ia, 123 units/mg, isoenzyme Ib, 113 units/mg, isoenzyme II, 242 units/mg, 1 unit is defined as absorbance change at 420 nm of 0.1 per min Portulaca grandiflora

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
catechol + 1/2 O2 isoenzymes Ia, Ib and II, 90, 43 and 42% of activity with L-dopa respectively, no activity with L-tyrosine, D-tyrosine, hydroquinone and methylhydroquinone Portulaca grandiflora 1,2-benzoquinone + H2O
-
?
D-dopa + 1/2 O2 isoenzymes Ia, Ib and II, 54, 60 and 48% of activity with L-dopa respectively Portulaca grandiflora D-dopaquinone + H2O
-
?
L-dopa + 1/2 O2
-
Portulaca grandiflora L-dopaquinone + H2O
-
?
pyrogallol + O2 isoenzymes Ia, Ib and II, 5, 8 and 15% of activity with L-dopa respectively Portulaca grandiflora ?
-
?

Subunits

Subunits Comment Organism
dimer 1 * 27000 + 1 * 25000, isoenzyme II, SDS-PAGE Portulaca grandiflora
monomer 1 * 65000, isoenzyme Ib, SDS-PAGE Portulaca grandiflora
monomer 1 * 66000, isoenzyme Ia, SDS-PAGE Portulaca grandiflora

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
5
-
isoenzymes Ia and Ib Portulaca grandiflora
6
-
isoenzyme II Portulaca grandiflora