Evaluation of amount of intracellular human BiP protein in yeast S. cerevisiae cells. (A) SDS–PAGE of crude yeast lysates and indicated amounts of purified BiP; (B) Western blot using polyclonal antibodies against human BiP. M – prestained protein ladder (ThermoScientific, cat. no. 26618). pFDC and pFDC-hBiP – crude lysates (10 μg of whole cell protein in each lane) of yeast cells transformed with pFDC vector and pFDC-hBiP plasmid, respectively. 50, 75, 100, 150, 200, 300, 400 – amounts in nanograms of purified secreted human BiP protein loaded on gel.