Periodate Oxidation of N-Terminal Serine or Threonine Residues

Periodate Oxidation of N-Terminal Serine or Threonine Residues 

The following protocol is based on the methods of Geoghegan and Stroh (1992) and Stolowitz et al. (2001). 

Dissolve the peptide containing an N-terminal serine or threonine group at a concentration of at least 2mg/ml in 0.04 M sodium phosphate, pH 7.0. Higher concentrations of peptides or proteins may be used without modification to the rest of the protocol, because the amount of periodate used in the reaction is in sufficient molar excess, even when low-molecular-weight peptides are being oxidized. Peptides that are initially insoluble 

With mixing, add sodium periodate to a final concentration of 2.5 mM. Periodate should be pre-dissolved as a stock solution at a higher concentration in buffer or water, and then 

React for 3 minutes at room temperature. Longer reactions increase the likelihood of oxidative damage to other amino acids within the peptide structure. 

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