Purification of murine liver-derived inhibitory protein.

Murine liver-derived inhibitory protein (LIP) capable of inhibiting human lymphocyte proliferation was separated from liver extract. The steps of purification included ammonium sulfate precipitation, DEAE-cellulose and hydroxylapatite ion exchange chromatographies, and gel filtration. The purified LIP appeared to be highly homogeneous, as verified by polyacrylamide gel electrophoresis (PAGE) and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). There was arginase activity in the LIP Preparation.