Biomaterial Database

Binding of calcium ions to the isolated asialo-glycoprotein receptor. Implications for receptor function in suspended hepatocytes. 1982

R Blomhoff, and H Tolleshaug, and T Berg

The binding of calcium ions by the isolated asialoglycoprotein receptor of hepatocytes and the inter-relationship between the calcium ion concentration and receptor function have been studied. The isolated receptor binds calcium ions only in the presence of asialoglycoprotein. The asialo-glycoprotein receptor complex binds 4 calcium ions; the binding exhibits marked positive cooperativity, and the association constant at half-saturation of the binding sites was of the order of 10*5) M-1 as determined from a Hill plot. The isolated receptor was almost saturated at a calcium ion concentration of 0.1 mM. The binding capacity of isolated hepatocytes for asialo-glycoproteins increased, however, even when the calcium concentration was increased above this level. This may be explained by the exposure of increasing numbers of functional receptors on the surface of the cell with increasing membrane potential, and this explanation is supported by analogous observations in the presence of 5 mM La3+.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008099	Liver	A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.	Livers
D009961	Orosomucoid		Acid Seromucoid,Seromucoid,Serum Sialomucin,alpha 1-Acid Glycoprotein,alpha 1-Acid Seromucoid,A(1)-Acid Seromucoid,Acid alpha 1-Glycoprotein,Alpha(1)-Acid Glycoprotein,alpha 1-Acid Glycoprotein (Acute Phase),alpha 1-Glycoprotein Acid,Acid alpha 1 Glycoprotein,Glycoprotein, alpha 1-Acid,Seromucoid, Acid,Seromucoid, alpha 1-Acid,Sialomucin, Serum,alpha 1 Acid Glycoprotein,alpha 1 Acid Seromucoid,alpha 1 Glycoprotein Acid
D011817	Rabbits	A burrowing plant-eating mammal with hind limbs that are longer than its fore limbs. It belongs to the family Leporidae of the order Lagomorpha, and in contrast to hares, possesses 22 instead of 24 pairs of chromosomes.	Belgian Hare,New Zealand Rabbit,New Zealand Rabbits,New Zealand White Rabbit,Rabbit,Rabbit, Domestic,Chinchilla Rabbits,NZW Rabbits,New Zealand White Rabbits,Oryctolagus cuniculus,Chinchilla Rabbit,Domestic Rabbit,Domestic Rabbits,Hare, Belgian,NZW Rabbit,Rabbit, Chinchilla,Rabbit, NZW,Rabbit, New Zealand,Rabbits, Chinchilla,Rabbits, Domestic,Rabbits, NZW,Rabbits, New Zealand,Zealand Rabbit, New,Zealand Rabbits, New,cuniculus, Oryctolagus
D011956	Receptors, Cell Surface	Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.	Cell Surface Receptor,Cell Surface Receptors,Hormone Receptors, Cell Surface,Receptors, Endogenous Substances,Cell Surface Hormone Receptors,Endogenous Substances Receptors,Receptor, Cell Surface,Surface Receptor, Cell
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001212	Asialoglycoproteins	Endogenous glycoproteins from which SIALIC ACID has been removed by the action of sialidases. They bind tightly to the ASIALOGLYCOPROTEIN RECEPTOR which is located on hepatocyte plasma membranes. After internalization by adsorptive ENDOCYTOSIS they are delivered to LYSOSOMES for degradation. Therefore receptor-mediated clearance of asialoglycoproteins is an important aspect of the turnover of plasma glycoproteins. They are elevated in serum of patients with HEPATIC CIRRHOSIS or HEPATITIS.	Asialoglycoprotein,Desialylated Glycoproteins,Glycoproteins, Desialylated
D037263	Asialoglycoprotein Receptor	A C-type lectin that is a cell surface receptor for ASIALOGLYCOPROTEINS. It is found primarily in the LIVER where it mediates the endocytosis of serum glycoproteins.	Asialoglycoprotein Receptors,ASGP-R,Asialoorosomucoid Receptor,Asialoorosomucoid Receptors,Asialoorosomucoid-Binding Protein,Hepatic Asialoglycoprotein Receptor,Hepatic Lectin,Liver Carbohydrate-Binding Protein,Receptor, Asialoglycoprotein,Receptor, Asialoorosomucoid,Asialoglycoprotein Receptor, Hepatic,Asialoorosomucoid Binding Protein,Carbohydrate-Binding Protein, Liver,Lectin, Hepatic,Liver Carbohydrate Binding Protein,Receptor, Hepatic Asialoglycoprotein,Receptors, Asialoglycoprotein,Receptors, Asialoorosomucoid
D066298	In Vitro Techniques	Methods to study reactions or processes taking place in an artificial environment outside the living organism.	In Vitro Test,In Vitro Testing,In Vitro Tests,In Vitro as Topic,In Vitro,In Vitro Technique,In Vitro Testings,Technique, In Vitro,Techniques, In Vitro,Test, In Vitro,Testing, In Vitro,Testings, In Vitro,Tests, In Vitro,Vitro Testing, In