D-3-Phosphoglycerate dehydrogenase from chicken liver. I. Purification

A method is described for the preparation of homogeneous D-3-phosphoglycerate dehydrogenase from chicken liver in amounts sufficient for structural studies. The procedure utilizes ammonium sulfate precipitation, blue dextran-Sepharose chromatography, ion exchange chromatography on phosphocellulose, and crystallization. Previous reports of instability of the enzyme have been shown to be due to proteolysis in the crude extract which can be effectively prevented by leupeptin. The purified enzyme is a basic protein with a pI of 8.95 as measured by isoelectric focusing. The extinction coefficient at 278 nm of a 1% solution is 5.3.