Protein C Human Plasma. Protein C, Source: Human Plasma, Physical Form Description: In 20 mM Tris-HCl, 0.1 M NaCl, 1 mM Benzamidine -pH 7.4, Molecular Weight: 62 kDa, Purity: greater than or equal to 95%, Synonyms: Vitamin K-dependent protein C, Anticoagulant protein C, Size: 50 ug