title: Immunoglobulins and alpha 1-acid glycoprotein do not contribute to the cholesterol crystallization-promoting effect of concanavalin A-binding biliary protein.
abstract: Human bile contains cholesterol crystallization-stimulating proteins that can be isolated by concanavalin A-Sepharose chromatography. In the past few years an increasing number of different pronucleating proteins have been identified in the concanavalin A-binding fraction. In this study we attempted to estimate the relative contribution of a number of these proteins to total concanavalin A-binding pronucleating activity. For this purpose, concanavalin A-binding glycoproteins were isolated from gallbladder bile samples from 12 patients with gallstones. The role of IgA, IgG and IgM and alpha 1-acid glycoprotein was investigated by means of immunoextraction. No decrease in crystallization-promoting activity was observed after precipitation of more than 98% of the different immunoglobulins. In addition, removal of more than 95% of alpha 1-acid glycoprotein from different concanavalin A-binding fractions had no significant effect on cholesterol crystallization-promoting activity. The influence of fibronectin was estimated by addition of physiological concentrations to a model bile system. At these concentrations fibronectin did not promote crystallization. From these data we conclude that immunoglobulins, alpha 1-acid glycoprotein and probably also fibronectin do not significantly contribute to total concanavalin A-binding activity.
authors.affiliation: Division of Gastrointestinal and Liver Diseases, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: M A
authors.initials: MA
authors.lastname: de Bruijn
authors.forename: K S
authors.initials: KS
authors.lastname: Mok
authors.forename: T
authors.initials: T
authors.lastname: Out
authors.forename: G N
authors.initials: GN
authors.lastname: Tytgat
authors.forename: A K
authors.initials: AK
authors.lastname: Groen
mesh_terms: D001646:Bile / Q000378:metabolism*; D002784:Cholesterol / Q000737:chemistry*; D003460:Crystallization; D005353:Fibronectins / Q000378:metabolism; D005704:Gallbladder; D006023:Glycoproteins / Q000378:metabolism; D006801:Humans; D007136:Immunoglobulins / Q000378:metabolism / Q000502:physiology*; D009961:Orosomucoid / Q000378:metabolism / Q000502:physiology*; D011506:Proteins / Q000378:metabolism; D011952:Receptors, Concanavalin A / Q000378:metabolism / Q000502:physiology*
chemical_list: D005353:Fibronectins; D006023:Glycoproteins; D007136:Immunoglobulins; D009961:Orosomucoid; D011506:Proteins; D011952:Receptors, Concanavalin A; C027774:concanavalin A-binding glycoproteins; D002784:Cholesterol