Liver endothelium can remove and transport the glycoprotein transferrin (TF). During this process the molecules are desialylated; however, in contrast with other such glycoproteins, for example caeruloplasmin, only half of transported TF is desialylated. To explore which component of TF is desialylated, we double-labelled fully sialylated TF with [3H]sialic acid residues and a 125I-protein moiety. This was then ‘chased’ through purified liver endothelium in pulse-chase experiments. Endothelium-conditioned TF was fractionated on an RCA120 affinity column into sialylated and desialylated components. Each component was then re-fractionated on a concanavalin A affinity column, which separates the glycoprotein according to the branching pattern of its glycan chain. The desialylated fraction was eluted only as a triantennary component, whereas the non-desialylated fraction consisted only of bi- and tetra-antennary chains. The significance of this selective desialylation of triantennary chain of TF in the subsequent metabolism of its iron content and its possible role in the pathogenesis of alcohol-induced hepatic siderosis are discussed.
Research Article|October 15 1989
Desialylation of transferrin by liver endothelium is selective for its triantennary chain
Biochem J (1989) 263 (2): 491-496.
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S Irie, M Tavassoli; Desialylation of transferrin by liver endothelium is selective for its triantennary chain. Biochem J 15 October 1989; 263 (2): 491–496. doi: https://doi.org/10.1042/bj2630491
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