HUMAN L-FICOLIN - PLASMA-LEVELS, SUGAR SPECIFICITY, AND ASSIGNMENT OFITS LECTIN ACTIVITY TO THE FIBRINOGEN-LIKE (FBG) DOMAIN

Ficolins are characterised by the presence of collagen-like and fibrin ogen-like (FBG) sequences. Human L-ficolin is synthesised in the liver and secreted into blood circulation. In previous studies, it was show n to bind to N-acetyl-D-glucosamine (GlcNAc). In the present study, it s detailed sugar specificity and binding site have been investigated. It was found to bind to GlcNAc and GalNAc (N-acetyl-D-galactosamine) w hile showing no significant affinity for the precursor sugars. The str ucture in these molecules which is recognised by L-ficolin has been de duced to include an amide (-CO-NH-) or similar group. L-Ficolin was di gested with collagenase and the collagenase resistant FBG domain was s hown to bind to GlcNAc. Its levels in adult and cord blood-derived hum an plasma were also determined and showed that adult plasma contains a pproximately three times more L-ficolin than that of newborn babies. ( C) 1998 Federation of European Biochemical Societies.