Purification of rabbit tumor necrosis factor

Abstract
Rabbit tumor necrosis factor (TNF) was purified and shown by SDS‐PAGE to be a single protein of 18 kDa. TNF in 355 ml rabbit serum was precipitated with ammonium sulfate, and purified by repeated DEAE‐Sephadex and Sephacryl S‐200 chromatographies, and the final fractionation on Blue‐Sepharose 6B. By this procedure its yield was 22% and its specific activity was 2.4 × 107 U/mg protein. The sequence of the N‐terminal 20 amino acids was determined.