title: Biosynthesis of a D-amino acid in peptide linkage by an enzyme from frog skin secretions.
abstract: d-amino acids are present in some peptides from amphibian skin. These residues are derived from the corresponding L-amino acids present in the respective precursors. From skin secretions of Bombinae, we have isolated an enzyme that catalyzes the isomerization of an L-Ile in position 2 of a model peptide to D-allo-Ile. In the course of this reaction, which proceeds without the addition of a cofactor, radioactivity from tritiated water is incorporated into the second position of the product. The amino acid sequence of this isomerase could be deduced from cloned cDNA and genomic DNA. After expression of this cDNA in oocytes of Xenopus laevis, isomerase activity could be detected. Polypeptides related to the frog skin enzyme are present in several vertebrate species, including humans.
authors.affiliation: Institute of Molecular Biology, Austrian Academy of Sciences, Billrothstrasse 11, A-5020 Salzburg, Austria.
authors.forename: Alexander
authors.initials: A
authors.lastname: Jilek
authors.forename: Christa
authors.initials: C
authors.lastname: Mollay
authors.forename: Christa
authors.initials: C
authors.lastname: Tippelt
authors.forename: Jacques
authors.initials: J
authors.lastname: Grassi
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Mignogna
authors.forename: Johannes
authors.initials: J
authors.lastname: Müllegger
authors.forename: Veronika
authors.initials: V
authors.lastname: Sander
authors.forename: Christine
authors.initials: C
authors.lastname: Fehrer
authors.forename: Donatella
authors.initials: D
authors.lastname: Barra
authors.forename: Günther
authors.initials: G
authors.lastname: Kreil
mesh_terms: D000591:Amino Acid Isomerases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000096:biosynthesis* / Q000737:chemistry*; D029845:Amphibian Proteins / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D001001:Anura / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D007700:Kinetics; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000737:chemistry / Q000378:metabolism; D009865:Oocytes / Q000201:enzymology; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012867:Skin / Q000201:enzymology*; D013045:Species Specificity; D013237:Stereoisomerism; D014982:Xenopus laevis
chemical_list: D000596:Amino Acids; D029845:Amphibian Proteins; D018076:DNA, Complementary; D009842:Oligopeptides; D011994:Recombinant Proteins; D000591:Amino Acid Isomerases