Store at 4°C for frequent use. Stored at -20°C in a manual defrost freezer for two year without detectable loss of activity. Avoid repeated freeze-thaw cycles.

The thermal stability is described by the loss rate. The loss rate was determined by accelerated thermal degradation test, that is, incubate the protein at 37°C for 48h, and no obvious degradation and precipitation were observed. The loss rate is less than 5% within the expiration date under appropriate storage condition.