title: Identification of a Glu greater than Lys substitution in the activation segment of human pepsinogen A-3 and -5 isozymogens by peptide mapping using endoproteinase Lys-C.
abstract: The isozymogens PGA-3 and PGA-5 of human pepsinogen A were digested with endoproteinase Lys-C. The peptides were separated by reverse-phase HPLC. PGA-5 showed a peak strongly absorbing at 254 nm absent in PGA-3. Analysis of amino acid composition using the Pico-Tag methodology combined with DABITC-sequencing reveals the sequence Tyr-Phe-Pro-Gln-Trp-Lys (peptide 37-43 of the activation segment). This confirms a study at the DNA level by our group [16] suggesting a Glu greater than Lys mutation at position 43 in the activation segment of PGA-5. Furthermore, it is proposed that the number of genetic variants of PGA is higher than is actually seen by electrophoresis.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D010450:Endopeptidases; D004789:Enzyme Activation; D005753:Gastric Mucosa / Q000201:enzymology; D005971:Glutamates; D018698:Glutamic Acid; D006801:Humans; D007527:Isoenzymes / Q000235:genetics* / Q000378:metabolism; D008239:Lysine; D008666:Metalloendopeptidases; D008969:Molecular Sequence Data; D010435:Pepsinogens / Q000235:genetics* / Q000378:metabolism; D010449:Peptide Mapping
chemical_list: D005971:Glutamates; D007527:Isoenzymes; D010435:Pepsinogens; D018698:Glutamic Acid; D010450:Endopeptidases; D008666:Metalloendopeptidases; C039830:peptidyl-Lys metalloendopeptidase; D008239:Lysine