Study of primary amines for nucleophilic cleavage of cyanylated cystinyl proteins in disulfide mass mapping methodology.

In a study of primary (methyl to butyl) amines as nucleophiles for cyano-induced cleavage of cysteinyl proteins, methylamine was found to be superior to ammonia for cyanylation (CN)-based disulfide mass mapping methodology. Reaction conditions such as nucleophile concentration, temperature, and reaction time were systematically studied using ribonuclease A as a model protein. The CN-induced cleavage products were monitored using reverse-phase chromatography and matrix-assisted laser desorption ionization mass spectrometry.