Thiocyanate hydrolase is a cobalt-containing metalloenzyme with a cysteine-sulfinic acid ligand

Yoko Katayama*, Kanako Hashimoto, Hiroshi Nakayama, Hiroyuki Mino, Masaki Nojiri, Taka Aki Ono, Hiroshi Nyunoya, Masafumi Yohda, Koji Takio, Masafumi Odaka

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

43 Citations (Scopus)


Thiocyanate hydrolase (SCNase) purified from Thiobacillus thioparus THI115 hydrolyzes thiocyanate to carbonyl sulfide and ammonia. DNA sequences of the cloned genes revealed the close relation of SCNase to nitrile hydratase (NHase). The consensus sequences for coordination of the metal ion found in NHases were also conserved in the γ subunit of SCNase. Here, we showed that the SCNase contained one cobalt atom per αβγ heterotrimer. UV-vis absorption spectrum suggested that the cobalt exists as a non-corrin ion. Reduced SCNase showed an ESR signal characteristic of low-spin Co2+, which closely resembled that of the Co-type NHases. Mass spectrometry for the peptide fragment containing the metal-binding motif of the SCNase γ subunit indicated that the cysteine residue at position 131 was post-translationally oxidized to a cysteine-sulfinic acid. From these results, we concluded that SCNases and NHases form a novel non-corrin and/or non-heme protein family having post-translationally modified cysteine ligands.

Original languageEnglish
Pages (from-to)728-729
Number of pages2
JournalJournal of the American Chemical Society
Issue number3
Publication statusPublished - 2006 Jan 25
Externally publishedYes

ASJC Scopus subject areas

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


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