A process is provided for the preparation of albumin which has extremely
low levels of or is essentially free of colorants, metal ions, human
proteins, host proteins, fragments of albumin, polymers or aggregates of
albumin and viruses, and which is essentially non-glycated, relatively
high in free thiol and with an intact C-terminus. The process comprises
passing albumin (preferably expressed and secreted by transformed yeast)
through positive mode cation exchange and then positive mode anion
exchange chromatography. Other steps may also be employed,
ultrafiltration, gel permeation chromatography, affinity chromatography
binding the albumin by using blue dyes) and affinity chromatography
binding contaminants by using an aminophenylboronic acid resin. Elution
of albumin, with a compound having affinity for albumin, from a material
having no specific affinity for albumin is also disclosed, as is removal
of ammonium ions with a counter-ion.