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Title: Cyanide does more to inhibit heme enzymes, than merely serving as an active-site ligand

Highlights: • Cyanide (CN) is a well-studied toxic principle, known to inhibit heme-enzymes. • Inhibition is supposed to result from CN binding at the active site as a ligand. • Diverse heme enzymes’ CN inhibition profiles challenge prevailing mechanism. • Poor binding efficiency of CN at low enzyme concentrations and ligand pressures. • CN-based diffusible radicals cause ‘non-productive electron transfers’ (inhibition). - Abstract: The toxicity of cyanide is hitherto attributed to its ability to bind to heme proteins’ active site and thereby inhibit their activity. It is shown herein that the long-held interpretation is inadequate to explain several observations in heme-enzyme reaction systems. Generation of cyanide-based diffusible radicals in heme-enzyme reaction milieu could shunt electron transfers (by non-active site processes), and thus be detrimental to the efficiency of oxidative outcomes.
Authors:
 [1] ;  [2] ;  [1] ;  [2]
  1. Center for Biomedical Research, VIT University, Vellore, Tamil Nadu, 632014 India (India)
  2. REDOx Lab, PSG Institute of Advanced Studies, Avinashi Road, Peelamedu, Coimbatore, Tamil Nadu, 641004 (India)
Publication Date:
OSTI Identifier:
22416853
Resource Type:
Journal Article
Resource Relation:
Journal Name: Biochemical and Biophysical Research Communications; Journal Volume: 455; Journal Issue: 3-4; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; CATALASE; CATTLE; CONCENTRATION RATIO; CYANIDES; DOSES; ELECTRON TRANSFER; HEME; HYDROCYANIC ACID; INHIBITION; LIGANDS; MICROCOCCUS; OXIDASES; OXIDATION; PYROGALLOL; RADICALS; SULFONATES; TOXICITY