Serum folic acid activity (L. casei) in Sephadex gel chromatography.

The folic acid activity (FAA) of the protein zone in DEAE Sephadex A-50 chromatography of normal serum showed the following distribution: most (about 40%) was eluted with protein zone IV (alpha-2-macroglobulin), about 33% with protein zones II-III (transferrin), and the balance with zone V (albumin). In healthy human subjects the variations were relatively small. The repeatability of the chromatography in an individual was good.Towards the end of pregnancy the binding of FAA to protein zones II-III increased, while that to zone IV decreased. The return to normal started a few days after delivery. The binding to zones II-III was greatly increased in patients with pernicious anaemia but no neuropathy. It became normal during B(12) therapy. If the patient had neuropathy, his FAA chromatogram was close to normal. During therapy the amount of unbound FAA decreased rapidly. The use of diphenylhydantoin increased the binding of FAA to protein zone I and to zones II-III. In these patients the binding to protein zone IV was slighter than normal.