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Evidence for two C‐H‐cleaving intermediates in isopenicillin N synthase
Author(s) -
Krebs Carsten,
Tamanaha Esta,
Bollinger Joseph M.
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.195.1
Subject(s) - chemistry , enzyme , stereochemistry , atp synthase , reaction intermediate , heme , biochemistry , catalysis
The enzyme isopenicillin N synthase (IPNS) catalyzes the four‐electron oxidation of L‐alpha‐aminoadipoyl‐L‐Cys‐D‐Val to isopenicillin N, an important presursor for many antibiotics, at its mononuclear non‐heme‐Fe(II) center using O2 as the oxidant. Extensive work by Baldwin and co‐workers revealed that the reaction proceeds in two steps and suggested two distinct C‐H‐cleaving intermediates as the oxidants. We trapped and characterized both C‐H‐cleaving intermediates by a combination of kinetic and spectroscopic methods. The two intermediates are best described as formally Fe(III)‐superoxo and Fe(IV)‐oxo complexes.