title: [Primary structure of human protein pS2].
abstract: We have previously reported that pS2 mRNA expressed in cultured epithelial cells derived from a hormone-dependent breast carcinoma (MCF-7 cells) is also expressed in mucosa cells of normal human stomach. This mRNA encodes a putative 84 amino-acid-long protein, which is secreted by both cell types after elimination of a signal peptide. We report here the purification of the pS2 protein, its trypsin digestion and amino-acid sequencing. The MCF-7 cell-secreted protein is 60 amino-acid-long and its sequence is in complete agreement with that deduced from the mRNA sequence. The presence of an N-terminal glutamic acid indicates that the signal peptidase releases a 24 amino-acid-long signal peptide. Analysis of tryptic peptides derived from the secreted gastric pS2 protein indicates that the signal peptide and the sequence of the first 48 amino-acids are identical to those of secreted MCF-7 pS2 protein, although the N-terminal amino-acid of the gastric protein may be cyclized as a pyroglumatic acid.
authors.affiliation: Laboratoire de Génétique moléculaire des Eucaryotes du C.N.R.S., Strasbourg.
authors.forename: M C
authors.initials: MC
authors.lastname: Rio
authors.forename: P
authors.initials: P
authors.lastname: Lepage
authors.forename: P
authors.initials: P
authors.lastname: Diemunsch
authors.forename: C
authors.initials: C
authors.lastname: Roitsch
authors.forename: P
authors.initials: P
authors.lastname: Chambon
mesh_terms: D000478:Alkylation; D000595:Amino Acid Sequence; D001483:Base Sequence; D001943:Breast Neoplasms / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D003470:Culture Media; D003545:Cysteine / Q000032:analysis; D005753:Gastric Mucosa / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000235:genetics / Q000302:isolation & purification; D010084:Oxidation-Reduction; D010446:Peptide Fragments; D011506:Proteins; D012333:RNA, Messenger / Q000235:genetics; D000071163:Trefoil Factor-1; D014357:Trypsin; D014407:Tumor Cells, Cultured; D025521:Tumor Suppressor Proteins
chemical_list: D003470:Culture Media; D009363:Neoplasm Proteins; D010446:Peptide Fragments; D011506:Proteins; D012333:RNA, Messenger; C051838:TFF1 protein, human; D000071163:Trefoil Factor-1; D025521:Tumor Suppressor Proteins; D014357:Trypsin; D003545:Cysteine
vernacular_title: Structure primaire de la protéine humaine pS2.