Pseudotheonamides, serine protease inhibitors from the marine sponge Theonella swinhoei

Yoichi Nakao, Akito Masuda, Shigeki Matsunaga, Nobuhiro Fusetani*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

47 Citations (Scopus)


Six new peptides with serine protease inhibitory activity have been isolated from the marine sponge Theonella swinhoei. Their structures including absolute stereochemistry were unambiguously established by interpretation of spectral data and chemical degradation. Pseudotheonamides A1 (1), A2 (2), and B2 (3) are linear pentapeptides embracing the rare piperazinone and piperidinoiminoimidazolone ring systems. Pseudotheonamide C (4) contains v-Tyr (vinylogous tyrosine) instead of a piperazinone ring. Pseudotheonamide D (5) is a tetrapeptide which lacks a C-terminal k-Arg (α- ketohomoarginine) unit. Dihydrocyclotheonamide A (6) is a reduction product of the known cyclotheonamide A (7).

Original languageEnglish
Pages (from-to)2425-2431
Number of pages7
JournalJournal of the American Chemical Society
Issue number11
Publication statusPublished - 1999 Mar 24
Externally publishedYes

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry


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