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Polyphenol Oxidase - Assay

Source:
Mushrooms (Agaricus bisporus)
CAS:
9002-10-2
EC:
1.14.18.1
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Polyphenol Oxidase Assay

Method
Polyphenol oxidase oxidizes tyrosine to dihydroxyphenylalanine which in turn is oxidized to o-quinone. The latter is accompanied by an increase in absorbance at 280 nm. The rate of increase is proportional to enzyme concentration and linear during a period of 5-10 minutes after an initial lag. One unit causes a change in absorbance at 280 nm of 0.001 per minute at 25°C, pH 6.5 under the specified conditions.
Reagents
  • 0.5 M Potassium phosphate buffer, pH 6.5
  • 0.001 M L-Tyrosine
Enzyme

Dissolve at a concentration of 1 mg/ml in reagent grade water. Dilute further in reagent grade water to a concentration of 200-400 units/ml.

Procedure

Adjust the spectrophotometer to 280 nm and 25°C. Pipette into each cuvette as follows:

0.5 M Phosphate buffer, pH 6.5 1.0 ml
0.001 M L-Tyrosine 1.0 ml
Reagent grade water 0.9 ml

Oxygenate this reaction mixture by bubbling oxygen into cuvettes through a capillary tube for 4-5 minutes. Transfer cuvettes to the spectrophotometer and record A280 for 4-5 minutes to achieve temperature equilibration and to establish blank rate, if any. Add 0.1 ml of appropriately diluted enzyme and record A280 for 10-12 minutes. Determine ΔA280 from the linear portion of the curve. A non-linear "lag" of 2-3 minutes can be expected.

Calculation

Polyphenol Oxidase Products

Description
Activity
Code
Cat. #
Size
Price
Description
Polyphenol Oxidase (Tyrosinase)
Source:
Mushrooms (Agaricus bisporus)
A lyophilized powder. Store at -20°C. Requires special shipping: Ice Pack.
Store at -20°C.
…
Ice Pack required
Activity
≥500 units per mg dry weight
Code
TY
LS003789
25 ku
$46.00
LS003792
100 ku
$121.00
LS003793
500 ku
$347.00
LS003791
Bulk
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The minimum amount for bulk packaging/pricing for this product is 10000 x 1 ku. Please contact custservice@worthington-biochem.com to request a quote for smaller amounts.