Background: Protein S (PS) is a natural anticoagulant that has a vital function in regulating
hemostasis and inflammation. Recently, the physiological and functional aspects of PS have gained
considerable attention, whereas the biophysical properties of PS are far less well defined.
Objective: In this study, our goal was to improve the yield of recombinant PS with minimal contamination
by endogenous, host cell PS.
Method: PS-stable cell lines were exposed to external factors and analyzed by qPCR and immunoblotting
for endogenous and exogenous PS levels.
Results: Glucose treatment decreased the overall yield of endogenous and exogenous PS, hydrogen peroxide
treatment increased the yield of both endogenous and exogenous PS, and calcium chloride treatment
increased secretion of exogenous PS without affecting secretion of endogenous PS.
Conclusion: Supplementation of the expression medium with 5 mM calcium chloride improves the
yield of recombinant PS.