Cobalamin R binder as a possible model molecule for glycoprotein study in cystic fibrosis.
The isoprotein pattern of semi-purified R binder (an acidic glycoprotein which binds cobalamin) from saliva and sera of 8 cystic fibrosis patients was compared to that of R binder from samples of 5 healthy children. In cases of cystic fibrosis, the mean isoelectric point of salivary R binder was increased from 3.78 up to 4.34 and its microheterogeneity was reduced. These significant physicochemical modifications were not observed with R binder from cystic fibrosis sera and they did not correlate with the beta-galactosidase, alpha-mannosidase, alpha-L-fucosidase nor neuraminidase activity of saliva. We propose the R binder as a model molecule to study the glycoprotein metabolism in cystic fibrosis since it contains 30-40% carbohydrate, is easily complexed with cyano[57Co]cobalamin and is present in most tissues and fluids of the human organism.
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003550:Cystic Fibrosis / Q000097:blood / Q000201:enzymology / Q000378:metabolism*; D006023:Glycoproteins / Q000378:metabolism*; D006801:Humans; D007525:Isoelectric Focusing; D008361:Mannosidases / Q000378:metabolism; D009439:Neuraminidase / Q000378:metabolism; D011485:Protein Binding; D012463:Saliva / Q000378:metabolism*; D014155:Transcobalamins / Q000097:blood / Q000378:metabolism*; D005644:alpha-L-Fucosidase / Q000378:metabolism; D043323:alpha-Mannosidase; D001616:beta-Galactosidase / Q000378:metabolism
D006023:Glycoproteins; D014155:Transcobalamins; D008361:Mannosidases; D009439:Neuraminidase; D001616:beta-Galactosidase; D043323:alpha-Mannosidase; D005644:alpha-L-Fucosidase