Biomaterial Database

Synthetic peptides with the biological activities and specificity of human C3a anaphylatoxin. 1977

T E Hugli, and B W Erickson

Two peptides identical to the COOH-terminal sequence of human C3a anaphylatoxin and two analogs were synthesized by the solid-phase method and tested for biological activity. The synthetic COOH-terminal octapeptide, C3a-(70-77) or Ala-Ser-His-Leu-Gly-Leu-Ala-Arg, caused contraction of guinea pig ileum and uterus, release of vasoactive amines from rat mast cells, and increased vascular permeability in guinea pig and human skin. On a molar basis, the synthetic octapeptide possessed 1-2% of the biological activities of C3a and specifically desensitized smooth muscle to stimulation by C3a. Like natural C3a, the synthetic C3a=(70-77) was inactivated by digestion with carboxypeptidase B [peptidyl-L-lysine(-L-arginine) hydrolase, EC 3.4.12.3], which removed the essential COOH-terminal arginine. A synthetic nonapeptide [C3a-(70-77)-Gly], containing a glycyl instead of an arginyl COOH terminus, was approximately 1% as active as the octapeptide when assayed with smooth muscle. The COOH-terminal 13-residue peptide of C3a, C3a-(65-77), was equal in activity to C3a=(70-77); similarly, C3a-(65-77)-Gly expressed the same activity as C3a-(70-77)Gly. It is concluded that both the biological specificity and the activity of human C3a anaphylatoxin are determined by eight or fewer residues located at the COOH terminus of the natural protein. However, expression of full activity requires additional groups and the secondary conformational integrity of the C3a molecule.

UI	MeSH Term	Description	Entries
D007082	Ileum	The distal and narrowest portion of the SMALL INTESTINE, between the JEJUNUM and the ILEOCECAL VALVE of the LARGE INTESTINE.
D008407	Mast Cells	Granulated cells that are found in almost all tissues, most abundantly in the skin and the gastrointestinal tract. Like the BASOPHILS, mast cells contain large amounts of HISTAMINE and HEPARIN. Unlike basophils, mast cells normally remain in the tissues and do not circulate in the blood. Mast cells, derived from the bone marrow stem cells, are regulated by the STEM CELL FACTOR.	Basophils, Tissue,Basophil, Tissue,Cell, Mast,Cells, Mast,Mast Cell,Tissue Basophil,Tissue Basophils
D009119	Muscle Contraction	A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.	Inotropism,Muscular Contraction,Contraction, Muscle,Contraction, Muscular,Contractions, Muscle,Contractions, Muscular,Inotropisms,Muscle Contractions,Muscular Contractions
D009130	Muscle, Smooth	Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)	Muscle, Involuntary,Smooth Muscle,Involuntary Muscle,Involuntary Muscles,Muscles, Involuntary,Muscles, Smooth,Smooth Muscles
D009842	Oligopeptides	Peptides composed of between two and twelve amino acids.	Oligopeptide
D010455	Peptides	Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are considered to be larger versions of peptides that can form into complex structures such as ENZYMES and RECEPTORS.	Peptide,Polypeptide,Polypeptides
D002199	Capillary Permeability	The property of blood capillary ENDOTHELIUM that allows for the selective exchange of substances between the blood and surrounding tissues and through membranous barriers such as the BLOOD-AIR BARRIER; BLOOD-AQUEOUS BARRIER; BLOOD-BRAIN BARRIER; BLOOD-NERVE BARRIER; BLOOD-RETINAL BARRIER; and BLOOD-TESTIS BARRIER. Small lipid-soluble molecules such as carbon dioxide and oxygen move freely by diffusion. Water and water-soluble molecules cannot pass through the endothelial walls and are dependent on microscopic pores. These pores show narrow areas (TIGHT JUNCTIONS) which may limit large molecule movement.	Microvascular Permeability,Permeability, Capillary,Permeability, Microvascular,Vascular Permeability,Capillary Permeabilities,Microvascular Permeabilities,Permeabilities, Capillary,Permeabilities, Microvascular,Permeabilities, Vascular,Permeability, Vascular,Vascular Permeabilities
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
D003176	Complement C3	A glycoprotein that is central in both the classical and the alternative pathway of COMPLEMENT ACTIVATION. C3 can be cleaved into COMPLEMENT C3A and COMPLEMENT C3B, spontaneously at low level or by C3 CONVERTASE at high level. The smaller fragment C3a is an ANAPHYLATOXIN and mediator of local inflammatory process. The larger fragment C3b binds with C3 convertase to form C5 convertase.	C3 Complement,C3 Precursor,Complement 3,Complement C3 Precursor,Complement Component 3,Precursor-Complement 3,Pro-C3,Pro-Complement 3,C3 Precursor, Complement,C3, Complement,Complement, C3,Component 3, Complement,Precursor Complement 3,Precursor, C3,Precursor, Complement C3,Pro C3,Pro Complement 3
D005260	Female		Females