Title : Natural human tumor necrosis factor beta ( lymphotoxin )
Abstract :
Variable O-glycosylation at Thr7 , proteolytic processing, and allelic variation
Natural human tumor necrosis factor beta ( TNF-beta ) purified from supernatants of a human B-lymphoblastoid cell line was found to be heterogeneous in molecular mass, with seven components resolved by gel electrophoresis
All components are N-glycosylated at Asn62 ; N-glycosylation does not contribute to heterogeneity
In addition, part of the molecules are O-glycosylated at Thr7 ; O-glycosylation is heterogeneous due to variable decoration with neuraminic acid.
The four lower molecular mass forms are derived from the full-length protein by trypsin-like proteolytic cleavage in the N-proximal region ; these clipped molecules lack O-linked carbohydrates
Two allelic variants differing in amino acid position 26 (threonine/asparagine) were identified