Schlorke Denise, Flemmig Jörg, Birkemeyer Claudia, Arnhold Jürgen
Institute for Medical Physics and Biophysics, Medical Faculty, University of Leipzig, Leipzig, Germany.
Institute for Medical Physics and Biophysics, Medical Faculty, University of Leipzig, Leipzig, Germany.
J Inorg Biochem. 2016 Jan;154:35-41. doi: 10.1016/j.jinorgbio.2015.11.005. Epub 2015 Nov 3.
The haem protein lactoperoxidase (LPO) is an important component of the anti-microbial immune defence in external secretions and is also applied as preservative in food, oral care and cosmetic products. Upon oxidation of SCN(-) and I(-) by the LPO-hydrogen peroxide system, oxidised species are formed with bacteriostatic and/or bactericidal activity. Here we describe the formation of the inter(pseudo)halogen cyanogen iodide (ICN) by LPO. This product is formed when both, thiocyanate and iodide, are present together in the reaction mixture. Using (13)C nuclear magnetic resonance spectroscopy and gas chromatography-mass spectrometry we could identify this inter(pseudo)halogen after applying iodide in slight excess over thiocyanate. The formation of ICN is based on the reaction of oxidised iodine species with thiocyanate. Further, we could demonstrate that ICN is also formed by the related haem enzyme myeloperoxidase and, in lower amounts, in the enzyme-free system. As I(-) is not competitive for SCN(-) under physiologically relevant conditions, the formation of ICN is not expected in secretions but may be relevant for LPO-containing products.
血红素蛋白乳过氧化物酶（LPO）是外分泌液中抗微生物免疫防御的重要组成部分，也被用作食品、口腔护理和化妆品中的防腐剂。在LPO-过氧化氢系统将硫氰酸根离子（SCN⁻）和碘离子（I⁻）氧化后，会形成具有抑菌和/或杀菌活性的氧化产物。在此，我们描述了LPO形成（假）卤素碘化氰（ICN）的过程。当硫氰酸盐和碘化物同时存在于反应混合物中时，就会形成该产物。在碘化物的用量略超过硫氰酸盐的情况下，我们通过¹³C核磁共振光谱法和气相色谱-质谱联用技术鉴定出了这种（假）卤素。ICN的形成基于氧化碘物种与硫氰酸盐的反应。此外，我们还证明了相关的血红素酶髓过氧化物酶也能形成ICN，且在无酶系统中形成的量较少。由于在生理相关条件下I⁻对SCN⁻没有竞争性，因此预计在分泌物中不会形成ICN，但这可能与含LPO的产品有关。
