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Literature summary for 1.10.3.1 extracted from

  • Dalmadi, I.; Rapeanu, G.; Van Loey, A.; Smout, C.; Hendrickx, M.
    Characterization and inactivation by thermal and pressure processing of strawberry (Fragaria ananassa) polyphenol oxidase: a kinetic study (2006), J. Food Biochem., 30, 56-76.
No PubMed abstract available

General Stability

General Stability Organism
inactivation kinetics under high pressure treatment at different temperatures, modeling in connection with thermal inactivation kinetics, the partially purified enzyme is stable up to a pressure of 400 mPA at 25°C, 5% remaining activity at 800 MPa and 25°C, inactive at 700-900 MPa and 40-50°C, overview Fragaria x ananassa

Inhibitors

Inhibitors Comment Organism Structure
additional information kinetics of enzyme inactivation by temperature and pressure Fragaria x ananassa

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
additional information
-
additional information thermodynamics and Michaelis-Menten kinetics, modeling in connection with pressure inactivation kinetics, overview Fragaria x ananassa
5.95
-
catechol pH 5.0, 25°C Fragaria x ananassa

Metals/Ions

Metals/Ions Comment Organism Structure
Cu2+ a copper enzyme Fragaria x ananassa

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
catechol + 1/2 O2 Fragaria x ananassa
-
1,2-benzoquinone + H2O
-
?
additional information Fragaria x ananassa PPO oxidizes o-diphenolic compounds to the corresponding o-quinones in the presence of oxygen, subsequently the o-quinones polymerize with other o-quinones, proteins, amino acids etc., resulting in the formation of brown complexes, the enzyme is one of the main enzymes responsible for quality loss in strawberry taste due to phenolic degradation ?
-
?

Organism

Organism UniProt Comment Textmining
Fragaria x ananassa
-
cv. Elsanta
-

Purification (Commentary)

Purification (Comment) Organism
native enzyme partially, solubilization by Triton X-100 in presence of polyvinyl polypyrrolidone, 32.fold by ammonium sulfate fractionation and dialysis Fragaria x ananassa

Source Tissue

Source Tissue Comment Organism Textmining
fruit
-
Fragaria x ananassa
-

Specific Activity [micromol/min/mg]

Specific Activity Minimum [µmol/min/mg] Specific Activity Maximum [µmol/min/mg] Comment Organism
24.1
-
solubilized, crude enzyme Fragaria x ananassa
788.3
-
partially purified enzyme Fragaria x ananassa

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
catechol + 1/2 O2
-
Fragaria x ananassa 1,2-benzoquinone + H2O
-
?
additional information PPO oxidizes o-diphenolic compounds to the corresponding o-quinones in the presence of oxygen, subsequently the o-quinones polymerize with other o-quinones, proteins, amino acids etc., resulting in the formation of brown complexes, the enzyme is one of the main enzymes responsible for quality loss in strawberry taste due to phenolic degradation Fragaria x ananassa ?
-
?
additional information PPO oxidizes o-diphenolic compounds to the corresponding o-quinones in the presence of oxygen Fragaria x ananassa ?
-
?

Synonyms

Synonyms Comment Organism
phenol oxidase
-
Fragaria x ananassa
PPO
-
Fragaria x ananassa

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
25
-
assay at Fragaria x ananassa

Temperature Stability [°C]

Temperature Stability Minimum [°C] Temperature Stability Maximum [°C] Comment Organism
additional information
-
biphasic thermal inactivation kinetics Fragaria x ananassa
55
-
10 min, partially purified enzyme, loss of 50% activity Fragaria x ananassa
65
-
10 min, partially purified enzyme, almost complete inactivation Fragaria x ananassa

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
5
-
-
Fragaria x ananassa

pH Range

pH Minimum pH Maximum Comment Organism
3.5 7 inactive at pH 3.0 and pH 7.5, half-maximal activity at pH 3.5 and pH 6.2 Fragaria x ananassa