DETECTION AND CHARACTERIZATION OF NATIVE BETA-ENDORPHIN(1-31) IN BOVINE PITUITARY USING ELECTROSPRAY-IONIZATION, LIQUID SECONDARY-ION AND TANDEM MASS-SPECTROMETRY

The molecular ion of intact beta-endorphin(bovine,1-31) (BE), which wa s extracted from bovine pituitary, was determined by electrospray ioni zation mass spectrometry. Liquid secondary ion mass spectrometry deter mined the molecular masses of three peptides produced by trypsin diges tion of BE, and tandem mass spectrometry was used to determine the ami no acid sequence of the tryptic peptide BE(20-24). These data, in comb ination, were used to characterize BE in bovine pituitary.