期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1978
卷号：75
期号：5
页码：2215-2219
DOI：10.1073/pnas.75.5.2215
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Evidence is presented suggesting that hepatocytes contain a receptor that binds glycoproteins specifically through fucose in 1[->]3 linkage to N-acetylglucosamine. Human lactoferrin, which contains this type of linkage, is rapidly cleared from the circulation of mice after intravenous injection, and greater than 90% of the injected material is found in hepatocytes. Binding of lactoferrin is mediated through its carbohydrate groups, since its clearance is prolonged after periodate oxidation or after its oligosaccharide groups are extensively degraded with glycosidases. In addition, glycopeptides from lactoferrin inhibit lactoferrin clearance. That lactoferrin clearance is mediated through binding to its fucosyl groups is suggested for several reasons. First, transferrin and asialotransferrin, whose oligosaccharide groups are essentially structurally identical to those of lactoferrin but devoid of fucose, are not cleared on intravenous injection. Second, when fucose is incorporated into asialotransferrin by 1[->]3 N-acetylglucosamine fucosyl transferase, the resulting fucosylated derivative is cleared rapidly. Neither mannan nor derivatives of orosomucoid that are cleared by binding to receptors for galactose, N-acetylglucosamine, or mannose, inhibit clearance of lactoferrin although clearance is inhibited by fucoidin. Finally, glycoproteins containing fucose in 1 [->] 2 linkage to galactose or 1 [->] 6 linkage to N-acetylglucosamine do not inhibit lactoferrin clerance by the liver. Since clearance of other glycoproteins, such as human lactoperoxidase, also appears to be mediated through binding to the same hepatocyte receptor as lactoferrin, it is concluded that the fucose-specific receptor studied here may fulfill other functions than binding lactoferrin. Preliminary studies with liver homogenates and detergent extracts of liver show binding in vitro.
