title: Basic proline-rich proteins from human parotid saliva: complete covalent structures of proteins IB-1 and IB-6.
abstract: The complete amino acid sequences of two basic proline-rich proteins, IB-1 and IB-6, from human parotid saliva have been determined. Fragments for sequence analysis were obtained by enzymatic digestions. The proteins have molecular weights of 9571 (IB-1) and 11,530 (IB-6) and contain 34 and 39 mol % proline, respectively. IB-1 and IB-6 contain an identical sequence of 54 residues except for an alanine in position 52 of IB-6, where IB-1 has proline. An unusually high number of repeated sequences occurs in both molecules. IB-1 has a blocked amino-terminal residue, pyroglutamic acid, and also contains one phosphoserine residue in position 8. The relationship of these proteins to the basic proline-rich protein IB-9 [Kauffman, D., Wong, R., Bennick, A., & Keller, P. (1982) Biochemistry 21, 6558-6562] and to other salivary proline-rich proteins is discussed.
mesh_terms: D000595:Amino Acid Sequence; D006801:Humans; D008970:Molecular Weight; D010306:Parotid Gland / Q000032:analysis*; D010446:Peptide Fragments / Q000032:analysis; D010447:Peptide Hydrolases; D010455:Peptides / Q000302:isolation & purification*; D055232:Proline-Rich Protein Domains; D012463:Saliva / Q000032:analysis*; D012471:Salivary Proteins and Peptides / Q000302:isolation & purification*
chemical_list: D010446:Peptide Fragments; D010455:Peptides; D012471:Salivary Proteins and Peptides; D010447:Peptide Hydrolases