Evidence of an intermediate-size beta-endorphin-containing precursor molecule in bovine pituitary by mass spectrometry.

A new analytical system has been designed to characterize intermediate-sized precursor molecules from two different precursors-the preproenkephalin Abovine,1-263 precursor molecule, which produces methionine enkephalin and from the proopiomelanocortin, POMCbovine,1-265 precursor molecule, which produces beta-endorphin. A possible intermediate-sized precursor that leads to beta-endorphin was found in bovine pituitary by means of electrospray ionization mass spectrometry, in combination with gel permeation chromatography, reversed-phase high performance liquid chromatography, radioimmunoassay, trypsinolysis, and liquid secondary ion mass spectrometry.