The study investigated the effects of alkaline phosphatase (AP) dephosphorylation and protein kinase A (PKA) phosphorylation on μ-calpain activity and its sensitivity to temperature. The purified μ-calpain was treated with AP or PKA for 30 min at 30 °C to modulate its phosphorylation level. Samples were then incubated at controlled freezing point (− 1), 4, 25 and 37 °C, respectively. The results showed that PKA and AP had no influence on pH values of incubation solution. At − 1 and 4 °C, the degradation rate of μ-calpain was maximum in ...
