Purification of CnPC from plasma by immunoaffinity chromatography using HPC4. (A) Silver stained non-reduced 12% SDS-PAGE showing plasma protein fractions obtained over the course of purification. Five μg of protein was loaded into each lane. Lane 1: Whole plasma. Lane 2: Plasma protein fraction obtained after salt precipitation and exclusion of protein <30 kDa in size. Lane 3: Plasma protein fraction in the salt precipitate that did not bind to react with HPC4. Lane 4: Proteins obtained after salt precipitation and immunoaffinity purification. Proteins were ~75 kDa in size and migrated as two tightly spaced bands. Lane 5: Molecular weight markers. (B) Western blot of gel in (A) with antibody to peptide EDQVDPRLIDGK. Lane loads were the same as (A). A faint band was present after salt precipitation and removal of small proteins (lane 2). This band was more prominent after immunoaffinity purification (lane 4). (C) Densitometry profile of lane 2 in (B). (D) Densitometry profile of lane 4 in (B). This band was 37.59 times as dense as the highlighted band in lane 2.