Is it preferable to store Bottle 4 (Citrate lyase lyophisilate) from Citric Acid Assay Kit (K-CITR) at 4°C or -20°C between assays?

The Citric Acid Assay Kit  is supplied with three bottles of Citrate lyase lyophisilate which undissolved is stable for > 2 years at -20°C. For use in this assay, one bottle of Bottle 4 should be dissolved in 0.55 mL of distilled water as indicated in the Preparation of Reagent Solutions/Suspensions section on pg. 3 of the kit booklet.  Once dissolved, the citrate lyase solution is stable for 4 weeks at 4°C or > 6 months at -20°C.  If storing for longer than 2 weeks, it is recommended to store the solution in appropriately sized aliquots and store in polypropylene tubes at -20°C to avoid repetitive freeze-thaw cycles.

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