Assistance for cysteine counters

A new approach to counting cysteine groups in peptides could help unravel complex biological processes, according to researchers in Switzerland.

Studying peptides and their structures, often by mass spectrometry will lead to a greater understanding of biological processes.

Hubert Girault and colleagues from the Laboratoire d’Electrochimie Physique et Analytique in Lausanne carried out numerical simulations to study electrochemical tagging of peptides during mass spectrometry. The group modelled the kinetics of labelling with quinone tags the cysteines in a peptide. 

This spectrometric technique works in samples where some peptides have all their cysteines labelled and others have no cysteines labelled, allowing simultaneous analysis of both labelled and non-labelled peptides. The simulations show that this is possible only for peptides containing a maximum of five cysteine groups.

This method for counting cysteines in peptides has already been used to accelerate the identification of model proteins. Girault’s group hope their work will help in the understanding and future development of this mass spectrometric technique so that it can be applied to complex biological samples.

Madelaine Chapman