The changes in glycosylation after partial hepatectomy enhance collagen binding of vitronectin in plasma

Vitronectin is a multifunctional glycoprotein present in the extracellular matrix and plasma. Changes in rat vitronectin were studied during liver reg eneration after partial hepatectomy. Carbohydrate concentrations of vitrone ctin decreased to 2/3 of sham-operated rats at 24 h after partial hepatecto my. Carbohydrate composition and lectin reactivity indicated that N-glycosy lation and sialylation of vitronectin changed markedly after partial hepate ctomy, while amino acid composition did not change significantly, We previo usly showed that deN-glycosylation of vitronectin in vitro affects collagen binding among various ligands (Yoneda et al,, Biochemistry (1998) 37, 6351 -6360). Vitronectins from partially hepatectomized rats at 24 h were found to exhibit markedly enhanced binding to type I collagen. The effect of sial ylation on collagen binding was further examined using enzymatically deglyc osylated vitronectin of nonoperated rats, Collagen binding increased by 1.2 times after deN-glycosylation of vitronectin, while it increased more than 2.9 times after desialylation. Various glycosyltransferases in liver are k nown to change after partial hepatectomy, including the attenuation of N-ol igosaccharide transferase. The findings therefore suggest that the collagen binding of vitronectin is modulated by the alteration of peptide glycosyla tion caused by postoperative physiological changes of glycosyltransferases and that the change may contribute to tissue remodeling processes.