Biomaterial Database

Identification of the beta-endorphin-binding subunit of the SC5b-9 complement complex: S protein exhibits specific beta-endorphin-binding sites upon complex formation with complement proteins. 1989

A Hildebrand

Institut für Medizinische Mikrobiologie, Justus-Liebig-Universität, Giessen, F.R.G.

Beta-Endorphin has been reported to specifically interact with SC5b-9 complement complexes via non-opioid binding sites. Covalent cross-linking of [125I]beta H-endorphin to SC5b-9 and analysis of the cross-linking products by gel electrophoresis and subsequent autoradiography revealed a single specifically labelled species which was identical with the S protein subunit of the complement complex. In contrast to SC5b-9, no cross-linking of labelled beta-endorphin to subunits of C5b-9(m) could be observed, indicating that beta-endorphin binding to SC5b-9 was mediated exclusively via S protein. Beta-Endorphin binding to SC5b-9 was compared with binding to purified S protein. Whereas beta-endorphin binding to purified S protein was only modest, complex formation of S protein with complement proteins led to a strong increase in beta-endorphin-binding site concentration, compatible with the exposure of primarily cryptic beta-endorphin-binding sites on S protein.

UI	MeSH Term	Description	Entries
D011957	Receptors, Opioid	Cell membrane proteins that bind opioids and trigger intracellular changes which influence the behavior of cells. The endogenous ligands for opioid receptors in mammals include three families of peptides, the enkephalins, endorphins, and dynorphins. The receptor classes include mu, delta, and kappa receptors. Sigma receptors bind several psychoactive substances, including certain opioids, but their endogenous ligands are not known.	Endorphin Receptors,Enkephalin Receptors,Narcotic Receptors,Opioid Receptors,Receptors, Endorphin,Receptors, Enkephalin,Receptors, Narcotic,Receptors, Opiate,Endorphin Receptor,Enkephalin Receptor,Normorphine Receptors,Opiate Receptor,Opiate Receptors,Opioid Receptor,Receptors, Normorphine,Receptors, beta-Endorphin,beta-Endorphin Receptor,Receptor, Endorphin,Receptor, Enkephalin,Receptor, Opiate,Receptor, Opioid,Receptor, beta-Endorphin,Receptors, beta Endorphin,beta Endorphin Receptor,beta-Endorphin Receptors
D003165	Complement System Proteins	Serum glycoproteins participating in the host defense mechanism of COMPLEMENT ACTIVATION that creates the COMPLEMENT MEMBRANE ATTACK COMPLEX. Included are glycoproteins in the various pathways of complement activation (CLASSICAL COMPLEMENT PATHWAY; ALTERNATIVE COMPLEMENT PATHWAY; and LECTIN COMPLEMENT PATHWAY).	Complement Proteins,Complement,Complement Protein,Hemolytic Complement,Complement, Hemolytic,Protein, Complement,Proteins, Complement,Proteins, Complement System
D003167	Complement Activation	The sequential activation of serum COMPLEMENT PROTEINS to create the COMPLEMENT MEMBRANE ATTACK COMPLEX. Factors initiating complement activation include ANTIGEN-ANTIBODY COMPLEXES, microbial ANTIGENS, or cell surface POLYSACCHARIDES.	Activation, Complement,Activations, Complement,Complement Activations
D003432	Cross-Linking Reagents	Reagents with two reactive groups, usually at opposite ends of the molecule, that are capable of reacting with and thereby forming bridges between side chains of amino acids in proteins; the locations of naturally reactive areas within proteins can thereby be identified; may also be used for other macromolecules, like glycoproteins, nucleic acids, or other.	Bifunctional Reagent,Bifunctional Reagents,Cross Linking Reagent,Crosslinking Reagent,Cross Linking Reagents,Crosslinking Reagents,Linking Reagent, Cross,Linking Reagents, Cross,Reagent, Bifunctional,Reagent, Cross Linking,Reagent, Crosslinking,Reagents, Bifunctional,Reagents, Cross Linking,Reagents, Cross-Linking,Reagents, Crosslinking
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
D001615	beta-Endorphin	A 31-amino acid peptide that is the C-terminal fragment of BETA-LIPOTROPIN. It acts on OPIOID RECEPTORS and is an analgesic. Its first four amino acids at the N-terminal are identical to the tetrapeptide sequence of METHIONINE ENKEPHALIN and LEUCINE ENKEPHALIN.	Endorphin, beta,beta-Endorphin (1-31),beta Endorphin
D001667	Binding, Competitive	The interaction of two or more substrates or ligands with the same binding site. The displacement of one by the other is used in quantitative and selective affinity measurements.	Competitive Binding
D015938	Complement Membrane Attack Complex	A product of COMPLEMENT ACTIVATION cascade, regardless of the pathways, that forms transmembrane channels causing disruption of the target CELL MEMBRANE and cell lysis. It is formed by the sequential assembly of terminal complement components (COMPLEMENT C5B; COMPLEMENT C6; COMPLEMENT C7; COMPLEMENT C8; and COMPLEMENT C9) into the target membrane. The resultant C5b-8-poly-C9 is the "membrane attack complex" or MAC.	Complement Complex C5b-9,Membrane Attack Complex,C 5b-9,C5b-8-poly-C9,C5b-9,Cytolytic Terminal Complement Complex,Terminal Complement Complex,C5b 8 poly C9,Complement Complex C5b 9,Complement Complex, Terminal,Complex, Terminal Complement
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