Title : Differences in glycosylation pattern of human secretory ribonucleases
Abstract :
- The major secretory ribonuclease ( RNase ) of human urine ( RNase HUA) was isolated and sequenced by automatic Edman degradation and analysis of peptides and glycopeptides
- The isolated enzyme was shown to be free of other urine RNase activities by SDS /polyacrylamide-gel electrophoresis and activity staining
- It is a glycoprotein 128 amino acids long, differing from human pancreatic RNase in the presence of an additional threonine residue at the C-terminus
- It differs from the pancreatic enzyme in its glycosylation pattern as well, and contains about 45 sugar residues
- Each of the three Asn-Xaa-Ser/Thr sequences ( Asn-34, Asn-76, Asn-88 ) is glycosylated with a complex-type oligosaccharide chain
- Glycosylation at Asn-88 has not been observed previously in mammalian secretory RNases
- Preliminary sequence data on the major RNase of human seminal plasma have revealed no difference between it and the major urinary enzyme ; their similarities include the presence of threonine at the C-terminus
- The glycosylation pattern of human seminal RNase is very similar to that of the pancreatic enzyme
- The structural differences between the secretory RNases from human pancreas, urine and seminal plasma must originate from organ-specific post-translational modifications of the one primary gene product
- Detailed characterization of peptides and the results of gel filtration of tryptic and tryptic/chymotryptic digests of performic acid-oxidized RNase have been deposited as Supplementary Publication SUP 50146 (4 pages) at the British Library Lending Division, Boston Spa , Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem
- J. (1988) 249, 5