Combined reagent and application thereof, kit containing combined reagent and detecting method

The invention discloses a combined reagent and an application thereof, a kit containing the combined reagent and a detecting method, belongs to the biological product analysis detection field, and in particular, relates to a new method which can reasonably evaluate the biological activity of a recombinant human calcineurin B subunit (hereinafter referred to as rhCNB). The method is characterized in that bis(p-nitrophenyl)phosphoric acid (hereinafter referred to as pNPP) and other calcineurin substrates are adopted as a reaction substrate, specific activation of the rhCNB on protein phosphatase such as a recombinant human calcineurin A subunit (hereinafter referred to as rhCNA), an rhCNA mutant or an rhCNA spliceosome is utilized, and the reaction substrate is chromogenic; the absorbance of the reaction substrate is detected by a UV-visible spectrophotometric colorimetric method and is conversed to the biological activity of the rhCNB. Tests prove that the test results of the method have good repeatability and