Journal
JOURNAL OF INORGANIC BIOCHEMISTRY
Volume 104, Issue 7, Pages 759-764Publisher
ELSEVIER SCIENCE INC
DOI: 10.1016/j.jinorgbio.2010.03.009
Keywords
Hypochlorous acid; Myeloperoxidase; Monochloramine; Phosphatidylserine; Ammonium ions
Funding
- German Research Foundation [Transregio 67, A-06]
Ask authors/readers for more resources
The close association of the heme enzyme myeloperoxidase to phosphatidylserine epitopes on the surface of non-vital polymorphonuclear leukocytes (PMNs) and other apoptotic cells at inflammatory sites favours modifications of this phospholipid by myeloperoxidase products. As detected by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry, ammonium ions inhibit in a concentration-dependent manner the hypochlorous acid-mediated formation of aldehyde and nitrile products from 1,2-dipalmitoyl-sn-glycero-3-phosphoserine (DPPS). Concomitantly, the formation of monochloramine (NH2Cl) raises with increasing NH4+ concentrations. A transchlorination from monochlorinated O-phospho-L-serine to NH4+ with the formation of NH2Cl occurs only when extraordinary high NH4+ concentrations are applied. Due to the low rate of 0.044 M-1 s(-1) for this process, a transhalogenation reaction from transient chlorinated intermediates of the serine moiety to NH4+ can be ruled out as an important process contributing to the HOCl-mediated formation of NH2Cl. A significant formation of NH2Cl by myeloperoxidase interacting with DPPS in the presence of ammonium ions takes only place at acidic pH values around 5, a scenario that may occur in phagosomes of macrophages after the uptake of apoptotic PMNs. (C) 2010 Elsevier Inc. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available