Enzyme involved in degradation of isonitrile with a nitrogen‐carbon triple bond
2010; Wiley; Volume: 24; Issue: S1 Linguagem: Inglês
10.1096/fasebj.24.1_supplement.897.1
ISSN1530-6860
AutoresMichihiko Kobayashi, Hiroyoshi Sato, Yoshiteru Hashimoto,
Tópico(s)Enzyme function and inhibition
ResumoWe have studied microbial metabolism of nitrile [R‐CN] and its isomer, isonitrile [R‐NC], both of which contain a C‐N triple bond. Although isonitriles are widely distributed in nature, information on their biological metabolism is quite limited. We obtained isonitrile‐degradable microorganisms, clarified the degradation pathway and discovered two new enzymes. Isonitrile hydratase (InhA) from Pseudomonas putida catalyzes hydration of isonitrile to N‐substituted formamide [R‐NH‐CH(=O)]. N‐substituted formamide deformylase from Arthrobacter pascens converts N‐substituted formamide to amine and formate. They have been approved as new enzymes by NC‐IUBMB. The upstream metabolism of isonitriles remains unknown in A. pascens . Therefore, we here investigated it and discovered another new enzyme involved in isonitrile degradation. At first, we found that the highest activity of isonitrile hydratase was obtained by the addition of N‐benzylformamide to the Arthrobacter cells. The isonitrile hydratase designated InhB was purified from the cell‐free extracts, and found to act on isonitriles to yield the corresponding N‐substituted formamide. InhB exhibited maximum activity at pH 7.3–7.7. Western blot analysis of the purified InhB using the anti‐InhA polyclonal antibody revealed that the primary structure of InhB did not show any similarity to that of InhA.
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