Amino‐acid sequence study in peptides by mass spectometry—III Investigation of ethyoxycarbonyl‐peptide methyl esters

The utility of ethoxycarbonyl‐peptide methyl esters for mass spectrometric analysis is described. The ethoxycarbonyl group has important advantages over other protecting groups which are in use. The derivatives have high intensity; this greatly facilitates the interpretation of the fragmentation pattern. The spentra of the methyl esters of the ethoxycarbonyl derivatives of pro‐val, trp‐gly, gly‐ser, (cys)2, glutation (GSH), glu‐his‐phe, val‐tyr‐pro and val‐lys‐val‐tyr‐pro are given.