[8][9] In the beginning, protein C inhibitor(PCI) was originally identified in human plasma by Griffin and Marlar[10] and first isolation was performed by Suzuki et al.[11] Protein C inhibitor (PCI) can be isolated from human plasma using an ordinary chromatographic procedure consisting of barium citrate adsorption, polyethylene glycol fractionation, DEAE-Sepharose CL-6B treatment, ammonium sulfate fractionation, dextran sulfate-agarose chromatography, gel filtration on ACA-44, and DEAE-Sephacel chromatography.

[9] Heparin enhances the rate of inhibition leading to the conformational change in the structure of Protein C and other proteases.

[15] Protein C inhibitor interacts with lipid membrane subsequently leading to permeabilization of bacterial pathogen exerting the antimicrobial activity.

Protein C inhibitor a potent antimicrobial agent that have ability to destroy the bacterial cell wall, causing death of the bacteria.

[16] Protein C inhibitor significantly reduces fertilization by inhibiting both the binding and penetration of zona free hamster oocytes by human sperm.