title: Further evidence for the presence of a thiazoline ring in the isoleucylcysteine dipeptide intermediate in bacitracin biosynthesis.
abstract: Isoleucylcysteine dipeptide, a first intermediate peptide in bacitracin biosynthesis, was liberated from the enzyme protein and oxidized with manganese dioxide in dimethylsulfoxide. The resulting oxidation product was identified by thin-layer chromatography as 2-(2-methyl-l-oxobutyl)-thiazole-4-carboxylic acid which has been isolated from the hydrolysate of bacitracin F. This result shows that the intermediate dipeptide contains a thiazoline ring, and that the thiazoline ring is synthesized at the dipeptide stage in the process of peptide chain elongation in bacitracin biosynthesis. Improbability of non-enzymatic dehydrative cyclization of the dipeptide is discussed.
authors.affiliation: Department of Agricultural Chemistry, Tohoku University, Sendai, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Ishihara
authors.forename: K
authors.initials: K
authors.lastname: Shimura
mesh_terms: D001414:Bacitracin / Q000096:biosynthesis*; D002250:Carbon Radioisotopes; D004151:Dipeptides / Q000138:chemical synthesis*; D007202:Indicators and Reagents; D009097:Multienzyme Complexes / Q000378:metabolism*; D010453:Peptide Synthases / Q000378:metabolism*; D013844:Thiazoles
chemical_list: D002250:Carbon Radioisotopes; D004151:Dipeptides; D007202:Indicators and Reagents; D009097:Multienzyme Complexes; D013844:Thiazoles; C054633:isoleucylcysteine; D001414:Bacitracin; D010453:Peptide Synthases; C019761:bacitracin synthetase