Biomaterial Database

Human C4b-binding protein, C4bp. Chymotryptic cleavage and location of the 48 kDa active fragment within C4bp. 1983

S Nagasawa, and H Unno, and C Ichihara, and J Koyama, and T Koide

C4bp, a regulator of the classical pathway of complement system, is composed of 6-8 disulfide-linked subunit chains of 75 kDa. Upon incubation with chymotrypsin, C4bp was rapidly cleaved into a nicked C4bp, composed of disulfide-linked 48 kDa and 27 kDa fragments. Subsequent slow cleavage on the 27 kDa fragment resulted in the liberation of the active site-containing 48 kDa fragment from the nicked C4bp. The N-terminal amino acid sequence of the 48 kDa fragment was identical to that of the parent subunit chain of C4bp, indicating that the 48 kDa active fragment was released from the N-terminal side of the parent subunit chain. Based on these results, a possible gross structure of C4bp is proposed.

UI	MeSH Term	Description	Entries
D007122	Immunoelectrophoresis	A technique that combines protein electrophoresis and double immunodiffusion. In this procedure proteins are first separated by gel electrophoresis (usually agarose), then made visible by immunodiffusion of specific antibodies. A distinct elliptical precipitin arc results for each protein detectable by the antisera.
D008958	Models, Molecular	Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.	Molecular Models,Model, Molecular,Molecular Model
D010446	Peptide Fragments	Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.	Peptide Fragment,Fragment, Peptide,Fragments, Peptide
D002352	Carrier Proteins	Proteins that bind or transport specific substances in the blood, within the cell, or across cell membranes.	Binding Proteins,Carrier Protein,Transport Protein,Transport Proteins,Binding Protein,Protein, Carrier,Proteins, Carrier
D002918	Chymotrypsin	A serine endopeptidase secreted by the pancreas as its zymogen, CHYMOTRYPSINOGEN and carried in the pancreatic juice to the duodenum where it is activated by TRYPSIN. It selectively cleaves aromatic amino acids on the carboxyl side.	Alpha-Chymotrypsin Choay,Alphacutanée,Avazyme
D003169	Complement Inactivator Proteins	Serum proteins that negatively regulate the cascade process of COMPLEMENT ACTIVATION. Uncontrolled complement activation and resulting cell lysis is potentially dangerous for the host. The complement system is tightly regulated by inactivators that accelerate the decay of intermediates and certain cell surface receptors.	Complement Cytolysis Inhibiting Proteins,Complement Cytolysis Inhibitor Proteins,Complement Inactivating Proteins,Serum Complement Inactivators,Complement Inactivators, Serum,Inactivating Proteins, Complement,Inactivator Proteins, Complement,Inactivators, Serum Complement,Proteins, Complement Inactivating,Proteins, Complement Inactivator
D006023	Glycoproteins	Conjugated protein-carbohydrate compounds including MUCINS; mucoid, and AMYLOID glycoproteins.	C-Glycosylated Proteins,Glycosylated Protein,Glycosylated Proteins,N-Glycosylated Proteins,O-Glycosylated Proteins,Glycoprotein,Neoglycoproteins,Protein, Glycosylated,Proteins, C-Glycosylated,Proteins, Glycosylated,Proteins, N-Glycosylated,Proteins, O-Glycosylated
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000595	Amino Acid Sequence	The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.	Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein
D046911	Macromolecular Substances	Compounds and molecular complexes that consist of very large numbers of atoms and are generally over 500 kDa in size. In biological systems macromolecular substances usually can be visualized using ELECTRON MICROSCOPY and are distinguished from ORGANELLES by the lack of a membrane structure.	Macromolecular Complexes,Macromolecular Compounds,Macromolecular Compounds and Complexes,Complexes, Macromolecular,Compounds, Macromolecular,Substances, Macromolecular