Beschreibung:
<jats:title>Abstract</jats:title><jats:p>The dipeptide antibiotic <jats:italic>N</jats:italic>‐valyl‐dihydroxyhomoproline (Val‐Dhp, <jats:bold>1</jats:bold>) was isolated from the culture filtrate of <jats:italic>Streptomyces antibioticus</jats:italic> ssp. <jats:italic>antibioticus</jats:italic> Tü 1718 by gel chromatography and HPLC. The purification, chemical, and spectroscopic characterization were hampered by complex equilibria between different forms of the highly hydrophilic antibiotic. The dipeptidic antibiotic crystallizes in thin needles. <jats:bold>1</jats:bold> consists of N‐terminal <jats:sc>L</jats:sc>‐valine coupled to a new dihydroxyimino acid related to <jats:sc>L</jats:sc>‐hydroxyproline. The results of <jats:sup>1</jats:sup>H NMR, <jats:sup>13</jats:sup>C NMR, mass (GC‐MS, FD) spectra and the comparison with synthetic <jats:sc>L</jats:sc>‐valyl‐<jats:sc>L</jats:sc>‐hydroxyproline are consistent with the proposed structure 2‐[1‐(2‐amino‐3‐methyl‐1‐oxobutyl)‐4‐hydroxy‐2‐pyrrolidinyl]‐2‐hydroxyetha‐noic acid. <jats:italic>N</jats:italic>‐Valyl‐dihydroxyhomoproline is active against <jats:italic>Escherichia coli</jats:italic> K 12, <jats:italic>Corynebacterium spec.</jats:italic>, and <jats:italic>Serratia marcescens</jats:italic>.</jats:p>