Rapid screening for S-adenosylmethionine-dependent methylation products by enzyme-transferred isotope patterns analysis
Article first published online: 6 JAN 2004
Copyright © 2003 John Wiley & Sons, Ltd.
Rapid Communications in Mass Spectrometry
Volume 18, Issue 3, pages 319–324, 15 February 2004
How to Cite
Wan, W., Zhao, G., Al-Saad, K., Siems, W. F. and Zhou, Z. S. (2004), Rapid screening for S-adenosylmethionine-dependent methylation products by enzyme-transferred isotope patterns analysis. Rapid Commun. Mass Spectrom., 18: 319–324. doi: 10.1002/rcm.1335
- Issue published online: 6 JAN 2004
- Article first published online: 6 JAN 2004
- Manuscript Revised: 21 NOV 2003
- Manuscript Accepted: 21 NOV 2003
- Manuscript Received: 9 SEP 2003
We report here an isotopic labeling and mass spectrometric method to rapidly identify S-adenosylmethionine (AdoMet)-dependent methylation products. In the presence of CH3- and CD3-labeled AdoMet, a methyl transfer product appears as a doublet separated by 3 Da in a mass spectrum, while other compounds show their normal isotopic distribution. Based on this unique isotopic pattern, methylation product(s) can be easily detected even from a mixture of cellular components. To validate our method, the product of human thiopurine methyltransferase (TPMT, EC 18.104.22.168) has been successfully identified from both an in vitro assay and a whole-cell assay. This method is generally applicable to AdoMet-dependent transmethylation and other group-transfer reactions, and constitutes the first example of a general strategy of enzyme-transferred isotope patterns (ETIPs) analysis. Copyright © 2004 John Wiley & Sons, Ltd.