Leukocytic Myeloperoxidase-Mediated Formation of Bromohydrins and Lysophospholipids from Unsaturated Phosphatidylcholines

---

O. M. Panasenko^1*, H. Spalteholz², J. Schiller², and J. Arnhold²

¹Research Institute of Physico-Chemical Medicine, ul. Malaya Pirogovskaya 1a, 119992 Moscow, Russia; fax: (7-495) 246-4490; E-mail: Oleg-Panasenko@newmail.ru

²Institute of Medical Physics and Biophysics, University of Leipzig, Haertelstr. 16-18, Leipzig 04107, Germany; fax: (49-341) 971-5709; E-mail: arnj@medizin.uni-leipzig.de

^* To whom correspondence should be addressed.

Received June 20, 2005; Revision received September 15, 2005

---

Using MALDI-TOF mass spectrometry, we have shown that leukocytic myeloperoxidase (MPO) in the presence of its substrates (H₂O₂ and Br^-) does not induce any changes in saturated 1,2-dipalmitoyl-sn-glycero-3-phosphocholine. Incubation of liposomes prepared from mono-unsaturated phosphatidylcholine (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) with the (MPO + H₂O₂ + Br^-) system resulted in formation of bromohydrins as the main products. 1-Palmitoyl-2-hydroxy-sn-glycero-3-phosphocholine (lysophosphatidylcholine) was the main product of the reaction of polyunsaturated phosphatidylcholine (1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine) with the (MPO + H₂O₂ + Br^-) system. The formation of lysophospholipids as well as of bromohydrins was not observed when the enzyme or one of its substrates (H₂O₂ or Br^-) was absent from the incubation medium, or if an inhibitor of MPO (sodium azide) or hypobromite scavengers (taurine or methionine) were added. Thus, it can be postulated that the formation of bromohydrins as well as lysophospholipids by the (MPO + H₂O₂ + Br^-) system results from reactions of hypobromite formed during MPO catalysis with double bonds of acyl chains of phosphatidylcholine. Such destructive processes may take place in vivo in membrane- or lipoprotein-associated unsaturated lipids in centers of inflammation.

---

KEY WORDS: myeloperoxidase, hypobromite, HOBr, unsaturated phospholipids, bromohydrin, lysophosphatidylcholine, MALDI-TOF mass spectrometry

DOI: 10.1134/S0006297906050178

---