Mass-spectrometric identification and sequence location of the ten residues of the new amino acid (γ-Carboxyglutamic acid) in the N-terminal region of prothrombin

Abstract

The identification and sequence location of .gamma.-carboxyglutamic acid was made by electron-impact and field-desorption studies on acetyl permethyl peptide derivatives and on the free amino acid. Details of the derivatives formed, and how this new amino acid may be easily recognized and sequenced from the mass spectrum, are given as a basis for future work.