Stoffwechselprodukte von Mikroorganismen 159. Mitteilung.Über die aromatische Aminosäure des Echinocandins B: 3,4-Dihydroxyhomotyrosin
作者:Walter Keller-Schierlein、Jörg Widmer
DOI:10.1002/hlca.19760590615
日期:——
The aromatic amino acid constituent of Echinocandin B: 3,4‐Dihydroxyhomotyrosine.The antifungal antibiotic echinocandin B gave upon treatment of its tetrahydroderivative with anhydrous trifluoroacetic acid and subsequent methanolysis the tripeptide threonyl‐(4‐hydroxyprolyl)‐(4‐oxohomotyrosine) methyl ester (8), which could be hydrolysed to 4‐oxohomotyrosine (11). These facts together with the earlier described hydrolysis of the antibiotic to 1‐amino‐3‐p‐hydroxyphenyl‐2‐propanone (6) and the reductive hydrolysis to homotyrosine suggested the presence of 3,4‐dihydroxyhomotyrosine (14) as a constituent amino acid of echinocandin B. This was confirmed by a degradation of the intact tetrahydro‐polypeptide with perjodate yielding p‐hydroxybenzaldehyde and by the isolation of free 3,4‐dihydroxyhomotyrosine upon mild acidic treatment of the tetrahydro‐polypeptide.
Fluorescent Analogues of the Insect Neuropeptide Helicokinin I: Synthesis,Photophysical Characterization and Biological Activity
In insects numerous physiological processes are regulated by neuropeptides. Two fluorescent analogues of the amino acids tryptophan and tyrosine were synthesized and incorporated in the diureticneuropeptidehelicokininI from the moth Heliothis zea. By fluorescence emission measurements it was shown that both fluorescent helicokininI analogues react sensitive on the dielectricity of their microenvironment
Stoffwechselprodukte von Mikroorganismen. 190. Mitteilung. Über das 4-Oxo-homotyrosin, ein Abbauprodukt des Echinocandins B
作者:Walter Keller-Schierlein、Beda Joos
DOI:10.1002/hlca.19800630125
日期:1980.1.23
D, L-4-Oxo-homotyrosine was synthesized by the acetylaminomalonic ester pathway. The optical resolution was carried out by means of the enzyme acylase I. The L-configuration of the enzymatically produced amino acid was confirmed by degradation to L-aspartic acid.