Resistance of Human Butyrylcholinesterase to Methylene Blue-Catalyzed Photoinactivation; Mass Spectrometry Analysis of Oxidation Products


TACAL Ö. , Li B., Lockridge O., Schopfer L. M.

PHOTOCHEMISTRY AND PHOTOBIOLOGY, cilt.89, sa.2, ss.336-348, 2013 (SCI İndekslerine Giren Dergi) identifier identifier identifier

  • Cilt numarası: 89 Konu: 2
  • Basım Tarihi: 2013
  • Doi Numarası: 10.1111/php.12016
  • Dergi Adı: PHOTOCHEMISTRY AND PHOTOBIOLOGY
  • Sayfa Sayıları: ss.336-348

Özet

Methylene blue, 3, 7-bis(dimethylamino)-phenothiazin-5-ium chloride, is a reversible inhibitor of human butyrylcholinesterase (BChE) in the absence of light. In the presence of light and oxygen, methylene blue promotes irreversible inhibition of human BChE as a function of time, requiring 3h irradiation to inhibit 95% activity. Inactivation was accompanied by a progressive loss of Coomassie-stained protein bands on native and denaturing polyacrylamide gels, suggesting backbone fragmentation. Aggregation was not detected. MALDITOF/TOF mass spectrometry identified oxidized tryptophan (W52, 56, 231, 376, 412, 490, 522), oxidized methionine (M81, 144, 302, 532, 554, 555), oxidized histidine (H214), oxidized proline (P230), oxidized cysteine (C519) and oxidized serine (S215). A 20min irradiation in the presence of methylene blue resulted in 17% loss of BChE activity, suggesting that BChE is relatively resistant to methylene blue-catalyzed photoinactivation and that therefore this process could be used to sterilize BChE preparations.