Analysis of the expression of rhP4H in P. pastoris GS115. The apparent molecular mass of rhP4H is ~60 kDa. (a) Detection of P4Hα2 and PDI at the mRNA level at different concentrations of Zecion. (b) SDS-PAGE analysis of the expression of rhP4H selected by 0.1, 0.5, 1.5, 2.5 and 3.5 mg/mL Zecion, respectively. M: middle molecular weight protein markers. (c) Western blotting analysis of PDI and P4Hα2 expression at different concentrations of Zecion. (d) SDS-PAGE analysis of the expression of rhP4H induced by 0.5, 1.0, 1.5, 2.0% methanol, respectively. M: middle molecular weight protein markers. (e) Western blotting analysis of the expression of PDI and P4Hα2 at different concentrations of methanol.