Substrate specificity of a peptidyl-aminoacyl-L/D-isomerase from frog skin.

ABSTRACT: In the skin of fire-bellied toads (Bombina species), an aminoacyl-L/D-isomerase activity is present which catalyses the post-translational isomerization of the L- to the D-form of the second residue of its substrate peptides. Previously, this new type of enzyme was studied in some detail and genes potentially coding for similar polypeptides were found to exist in several vertebrate species including man. Here, we present our studies to the substrate specificity of this isomerase using fluorescence-labeled variants of the natural substrate bombinin H with different amino acids at positions 1, 2 or 3. Surprisingly, this enzyme has a rather low selectivity for residues at position 2 where the change of chirality at the alpha-carbon takes place. In contrast, a hydrophobic amino acid at positio

SUBMITTER: Jilek A 

PROVIDER: S-EPMC3325411 | biostudies-literature | 2012 May

REPOSITORIES: biostudies-literature