3.5.3. Data analysis

1. Subtract the average background count (from the negative control samples) from each reading to correct for background noise.

2. Determine the quantity of JH the CA released into the medium by converting the cpm value obtained from the previous step into dpm counts taking into account the tritium sensitivity of your scintillation counter (counter sensitivity is determined by running a manufacturer supplied scintillation vial containing a specified amount of the isotope of interest; correct for half-life).

3. Convert this dpm value into pmol JH released, taking into account the specific activity (typically 70 Ci/mmol) of your labelled methionine: considering that 2.22 dpm = 1 pCi, a dpm value of 155,400 = 1 pmol JH.

4. Calculate the hourly release rate by dividing the pmol value obtained (step 3) by the duration of the incubation period (divide value by 3 if incubation was 3 h).

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