The preparation of porcine (Tyr-A14-2H) insulin and its characterization by mass spectrometry

The title compound was prepared by catalytic deiodination of(Tyr-A¹⁴-3-I) insulin with deuterium gas. Under special conditions(large excess of PdO in CH₃OD/D₂O at pH 9.2) developed to minimizeproblems due to poisoning of the catalyst, deuterated insulinwas produced in yields of about 35% after purification by reversedphase HPLC. For analysis, the deuterated insulin was digestedwith V8 protease and was shown by mass spectrometry to haveincorporated deuterium to an extent of 96.6 atom %, exclusivelyin a pentapeptide containing Tyr A¹⁴. The title compound shouldprove useful to those workers studying insulin by mass spectrometry,and use of the method with tritium gas in place of deuteriumshould permit the preparation of a specifically labelled radioactiveinsulin analogue which behaves identically to the natural hormone.