title: [Quaternary structure of Escherichia coli polynucleotide phosphorylase: chemical characterization of form A].
abstract: We had previously shown the existence of two classes of polynucleotide phosphorylases : Form A which is made of alpha chains and carries the catalytic sites ; and form B which is constituted of alpha chains and of beta chains. We performed some chemical analyses of form A (N-terminal sequence, amino acid composition, peptide mapping) which suggest that the alpha chains are all identical and moreover that they have no relationship with the beta chains. The latter do not therefore derive from a partial proteolytic degradation of the alpha chains and can therefore be considered as true subunits of the enzyme.
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000201:enzymology*; D046911:Macromolecular Substances; D010446:Peptide Fragments / Q000032:analysis; D011117:Polyribonucleotide Nucleotidyltransferase / Q000032:analysis*; D011487:Protein Conformation
chemical_list: D000596:Amino Acids; D046911:Macromolecular Substances; D010446:Peptide Fragments; D011117:Polyribonucleotide Nucleotidyltransferase
vernacular_title: Structure quaternaire de la polynucléotide phosphorylase dEscherichia coli : caractérisation dhimique de la forme A