The fractionation of human plasma proteins. III. Purification of complement factors D and I using affinity chromatography.

A purification protocol for complement factors D and I was designed as part of a larger scheme for the purification of more than 20 human plasma proteins. The key affinity step in the purification of both serine proteases, factors D and I, was affinity chromatography using benzamidine Sepharose. The recoveries were 19 and 12% for factors D and I, respectively.