title: Purification and structural studies on the complement-system control protein beta 1H (Factor H).
abstract: An efficient procedure for the isolation of the complement-system control protein beta 1H (Factor H) from human plasma was developed. The chemical composition and physical characteristics of the protein were studied, and a sequence of 17 amino acid residues at the N-terminus was determined. Factor H is a single-polypeptide-chain glycoprotein of mol.wt. 155 000 containing 9.3% carbohydrate. Factor H is cleaved by plasma proteinases to a two-chain form. This cleavage can be mimicked by trypsin, and the two-chain form retains fully the C3b-inactivator cofactor activity of Factor H. The proteolytic fragments of Factor H are compared with those of other proteins (C4b-binding protein and erythrocyte C3b-receptor) that act as cofactors for C3b-inactivator.
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D002241:Carbohydrates / Q000032:analysis; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D003180:Complement C3b Inactivator Proteins / Q000302:isolation & purification*; D017242:Complement Factor H; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D008970:Molecular Weight; D010446:Peptide Fragments / Q000032:analysis
chemical_list: D000596:Amino Acids; C493495:CFH protein, human; D002241:Carbohydrates; D003180:Complement C3b Inactivator Proteins; D010446:Peptide Fragments; D017242:Complement Factor H