Premium
Understanding the role of chelators in the Mn peroxidase reaction mechanism: a closer look at kinetics and Mn speciation
Author(s) -
Youngs Heather L.
Publication year - 2007
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.21.5.a642-c
Subject(s) - chelation , ternary complex , chemistry , ternary operation , kinetics , peroxidase , ligand (biochemistry) , reaction mechanism , catalysis , medicinal chemistry , combinatorial chemistry , enzyme , inorganic chemistry , receptor , organic chemistry , biochemistry , physics , quantum mechanics , computer science , programming language
The role of chelators in the Mn peroxidase (MnP) reaction cycle has long been a subject of debate. Chelators are required for turnover of the enzyme; however, the exact mechanism is not known. The evidence has been distilled into two conflicting theories: MnP binds free, unchelated Mn2+, oxidizes it and releases chelated Mn3+, either by mediated release (ligand exchange) or via a transient chelate‐Mn3+‐MnP complex. MnP binds and oxidizes chelated Mn2+ to form a ternary complex, which is then oxidized and released as a Mn3+‐chelate product. No proof of a ternary complex has surfaced in the last twenty year of study. I present a new evaluation of the kinetic data and corrected calculations of the Mn speciation under the optimal reaction conditions to assert that formation of a ternary complex is not required to account for the stimulation of activity by chelators in the MnP reaction mechanism.