Analysis of hydroxyl radical‐induced oxidation process of glucagon by reversed‐phase HPLC and ESI‐MS/MS |
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| Authors: | Hideaki Ichiba Tomoko Ogawa Takehiko Yajima Takeshi Fukushima |
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| Institution: | Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Toho University, 2‐2‐1 Miyama, Funabashi‐shi, Chiba 274‐8510, Japan |
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| Abstract: | Structural modification of a polypeptide hormone, glucagon, by a hydroxyl radical in vitro was investigated by reversed‐phase high‐performance liquid chromatography (RP‐HPLC), and the oxidized site of glucagon was detected by electrospray ionization tandem mass spectrometry (ESI‐MS/MS). It was shown that 27methionine (Met) was oxidized to 27Met sulfoxide by hydroxyl radical, and the production rate of 27Met sulfoxide was faster than that by hydrogen peroxide. In addition, production of 27Met sulfoxide enantiomer was confirmed by RP‐HPLC analysis. cAMP production in a HepG2 cell induced by 27Met sulfoxide glucagon was reduced to approximately 75% as compared with that induced by the native form of glucagon. Copyright © 2009 John Wiley & Sons, Ltd. |
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| Keywords: | glucagon RP‐HPLC ESI‐MS/MS Met sulfoxide |
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