Open AccessCovalent structure of chicken pepsinogen
Author(s) -
BAUDYŠ Miroslav,
KOSTKA Vladimir
Publication year - 1983
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1983.tb07709.x
Subject(s) - chemistry , chymotrypsin , trypsin , pepsin , biochemistry , protein primary structure , peptide sequence , moiety , amino acid , arginine , lysine , stereochemistry , residue (chemistry) , cleavage (geology) , aspartic acid , enzyme , biology , paleontology , fracture (geology) , gene
Chicken pepsinogen is a glycoprotein consisting of a single polypeptide chain and containing the following 367 amino acid residues: Asp 23 , Asn 16 , Thr 26 , Ser 41 , Glu 14 , Gln 11 , Pro 18 , Gly 31 , Ala 17 , Cys 7 , Val 25 , Met 9 , Ile 23 , Leu 28 , Tyr 22 , Phe 20 , His 8 , Lys 17 , Arg 7 , Trp 4 . The M r ‐value of the protein is 42074. This value includes the carbohydrate moiety of the protein, i.e. Man 3 , (GlcNAc) 7 , (‐SO 3 H) 5 . The primary fragmentation of the molecule was effected by limited trypsinolysis at arginine residues after preceding modification of the lysines with citraconic anhydride. All eight peptides expected in theory were obtained and their size, amino acid composition, and N‐terminal amino acid sequence were characterized. To elucidate the amino acid sequence of these large fragments the latter were subjected to secondary cleavage by CNBr, trypsin (after removal of the protecting groups from the lysines), the proteinase from Staphylococcus aureus V8 strain, α‐chymotrypsin, hydroxylamine, or dilute acid; the resulting peptides were isolated by gel permeation and ion‐exchange chromatography and by the fingerprint techniques. Overlaps at sites of the arginine residues were obtained in an earlier study [BaudyŠ, M. & Kostka, V. (1982) Collect. Czech. Chem. Commun. 47 , 2814–2832]. Chicken pepsinogen shows the highest degree of homology with the primary structures of pepsinogens A. The internal homologies are apparent in the neighborhood of the two active aspartic acid residues. We have assigned tentatively chicken pepsinogen to the group of pepsinogens A (EC 3.4.23.1); this assignment is a result both of our sequence studies and of an investigation of the kinetic characteristics of the enzyme.