Activity of partially purified UDP-N-acetyl-alpha-D-galactosamine: polypeptide N-acetylgalactosaminyltransferase with different peptide acceptors
Porowska, H.; Paszkiewicz-Gadek, A.; Gindzieński, A.
Acta Biochimica Polonica 46(2): 365-370
1999
ISSN/ISBN: 0001-527X PMID: 10547037 Document Number: 500542
As part of investigations on the role of the UDP-GalNAc-ribosome complex in the initial O-glycosylation of proteins, we have isolated from porcine gastric mucosa GalNAc-transferase, mucin and apomucin, and its three fractions containing carbohydrate in the amounts: I - 1.6%, II - 0.65% and III - 0.00% (wt/wt) of apomucin mass. Amino acid analysis showed that fractions I and II contained slightly higher amounts of serine and threonine as compared to native mucin and apomucin. The short peptide Pro-Thr-Ser-Ser-Pro-Ile-Ser-Thr was the most effectively glycosylated. Our apomucin preparations are also good acceptors of GalNac and can be used for testing of O-glycosylation in vitro.