Partial Characterization of Human C5a Anaphylatoxin I. Chemical Description of the Carbohydrate and Polypeptide Portions of Human C5a

摘要: Human C5a was isolated from complement-activated serum and characterized for protein carbohydrate content. The purified judged to be homogeneous by both polyacrylamide gel electrophoresis immunologic techniques. polypeptide moiety of contains 73 amino acid residues which represent a m.w. 8,200. Analysis the in indicated 4 moles glucosamine, 3 sialic acid, mannose 2 galactose. total content C5a, therefore, amounts approximately 25% apparent anaphylatoxin molecule. portions together equal 11,000 is considerably less than 15 16,000 physical measurements. COOH-terminal arginine essential activity sequence Gln-Leu-Gly-Arg-COOH at COOH-terminus compares favorably with that human C3a (Gly-Leu-Ala-Arg-COOH). Additional similarities between molecules include length chain, number disulfide bonds an absence tryptophan residues. A major chemical difference does exist these two anaphylatoxins, namely associated but absent partial NH2-terminal determined as NH2-Thr-Leu-Glx-Lys-Lys-Ile-Glx-Glx-Ile-Ala- direct comparison known shows little homology.