Hello everyone!

I need to measure NAD+/NADH levels using the NAD/NADH Quantification Kit (MAK037) from Sigma-Aldrich, and I´d like to know if I can first extract the supernatant containing NAD/NADH (Step 1 of sample preparation on the instruction manual) and then freeze it (-20°C or -80°C) for later measurement.

Is this recommended or would I loose NAD content? There would only be one freeze/thaw cycle after the extraction procedure to collect all samples before measurement.