Oxalate Decarboxylase Assay

Method: The reaction velocity is measured by a conventional Warburg manometric technique. One unit of activity releases one micromole of CO₂ per minute at 37°C and pH 3.0 under the specified conditions.

Reagents

• 1.0 M Potassium citrate, pH 3.0
• 0.1 M Potassium oxalate, pH 3.0

Enzyme

Dissolve enzyme at a concentration of 3-5 units/ml in reagent grade water.

Procedure

Into the bottom well of the Warburg flasks pipette as follows:

1.0 M Potassium citrate, pH 3.0	0.4 ml
Reagent grade water	2.4 ml
Diluted enzyme	0.1 ml

Pipette 0.1 ml of 0.1 M potassium oxalate, pH 3.0 into the side arm. Include one flask containing no enzyme as a blank and a flask containing 3.0 ml of water to serve as a thermal barometer. After ten minutes of equilibration, close the manometers, tip in and mix the substrate and replace the flasks in the bath. Read all the flasks every five minutes for 30 minutes.

Calculation