Isolation and characterization of a tumor necrosis factor binding protein from urine

Tumor necrosis factor (TNF)/cachectin can produce both beneficial and harmful manifestations. Mechanisms may operate to counteract potentially harmful effects such as shock and cachexia. The TNF binding protein (TNF‐BP), which is found at increased levels in serum and urine of patients with chronic renal failure, may play such a role. TNF‐BP was purified 1000000–fold to homogeneity from urine of patients with chronic renal failure by use of ion exchange chromatography, affinity chromatography on TNF‐Sepharose and reverese phase chromatography. The purified protein contained only one chain with an apparent M_r on sodium dodecyl sulfate‐polyacrylamide gel electrophoresis of 30000. The aminoterminal amino acid sequence D‐S‐V‐X‐P‐Q‐G‐K‐Y‐I‐H‐P‐Q‐V‐N‐S‐I‐X‐K‐T revealed no significant homologies with previously described protein sequences. TNF‐BP may act as a regulator of the bioactivities of TNF/cachectin.