Human insulin-like growth factor binding protein-6 is O-glycosylated.
Insulin-like growth factor binding protein-6 (IGFBP-6) is found in serum, cerebrospinal fluid and conditioned media from human fibroblasts. It has a marked preferential binding affinity for IGF-II over IGF-I. The present study demonstrates that IGFBP-6 purified from human cerebrospinal fluid is O-glycosylated but not N-glycosylated. Enzymatic deglycosylation does not alter the high affinity of IGFBP-6 for IGF-II (Ka 4.4 +/- 2.2 x 10(11) M-1) or its preference for IGF-II over IGF-I. The effect of glycosylation of IGFBP-6 on its secretion, in vivo stability or localization remains to be determined.
Bach
L A
LA
Growth and Development Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892.
Thotakura
N R
NR
Rechler
M M
MM
D001667:Binding, Competitive / Q000187:drug effects; D002240:Carbohydrate Sequence; D002352:Carrier Proteins / Q000134:cerebrospinal fluid / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D006031:Glycosylation; D006801:Humans; D018976:Insulin-Like Growth Factor Binding Protein 6; D007335:Insulin-Like Growth Factor II / Q000378:metabolism; D037102:Lectins / Q000378:metabolism; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000378:metabolism; D011485:Protein Binding; D013002:Somatomedins
D002352:Carrier Proteins; D018976:Insulin-Like Growth Factor Binding Protein 6; D037102:Lectins; D009844:Oligosaccharides; D013002:Somatomedins; D007335:Insulin-Like Growth Factor II