title: [The primary structure of human free secretory component and the arrangement of disulfide bonds].
abstract: The amino-acid sequence and the arrangement of the disulfide bonds of the human free secretory component were completely elucidated by the methods of protein chemistry. The free secretory component is a monomeric glycoprotein (Mr approximately 86000), consisting of 558 amino acids with 7 carbohydrate chains bound to asparagine. The protein contains 20 cysteine residues but, as a special feature, no methionine. The polypeptide chain is divided into five regions of internal homology, 104 to 114 amino acids in length. The 20 cysteine residues form 10 disulfide bonds, 9 of which confirm the internal homology by their characteristic arrangement. The free secretory component also shows homology to immunoglobulins in some sections. A computer-supported tertiary structure is proposed for the free secretory component.
mesh_terms: D000595:Amino Acid Sequence; D004220:Disulfides / Q000032:analysis*; D006023:Glycoproteins / Q000032:analysis*; D006801:Humans; D006868:Hydrolysis; D007070:Immunoglobulin A / Q000032:analysis; D011487:Protein Conformation
chemical_list: D004220:Disulfides; D006023:Glycoproteins; D007070:Immunoglobulin A; C026439:lung free secretory component protein, human
vernacular_title: Die Primärstruktur der menschlichen freien Sekretkomponente und die Anordnung der Disulfidbrücken.