| Budget Amount *help |
¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1996: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1995: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Research Abstract |
Many lanthionine-containing peptides have been found and studied. Furthermore, the biosynthetic mechanism of these peptide has been extensively studied. The growing activity in this field has necessitated a supply of authentic samples of various lanthionine peptides which may be better prepared by chemical synthesis. However, the time-consuming and tedious procedures in chemical synthesis of lanthionine peptides, particularly for preparation of synthon amino acids, such as the sterically pure methylcsteine, as well as the deslfurization step, and introduction of dehydroamino acid residues, might discourage plans for attempting new syntheses of lanthionine peptides.
In this situation, we attempted a novel strategy for synthesis of lanthionine peptide through an enzumic formation of lanthionine ring form open-chain peptide comprising a hydroxy amino acid and cysteine.
Lanthionine synthase was first isolated from the cell-free extract of a Streptomyces species by the following procedures : ammonium sulfate precipitation, dialysis, ion-exchange chromatography on DEAE-Sephacel, and gel filtration (Sephaedex G-25 and Sephadex G-150). The enzyme thus purified gave a single band on SDS-polyacrylamice gel electrophoresis.
We also examined the substrate specificity of the lanthionine synthase isolated from Streptomyces species. As the result of the reaction of several synthetic substrates, such as nisin propeptide, ancovenin propeptide, and some model peptides, the enzyme exhibited the broad substrate specificity except the length of the peptide and the cofiguration of the reaction site of the sbstrate.
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