MOLECULAR-WEIGHTS OF HIGH-MOLECULAR-WEIGHT SUBUNITS OF GLUTENIN DETERMINED BY MASS-SPECTROMETRY

High molecular weight (HMW) subunits of glutenin, corresponding to those for which full length gene sequences are available, were purified and their M(r)s determined by mass spectrometry [matrix-assisted laser desorption ionisation (MALDI)]. In general, the M(r)s determined were within the experimental error of the techniques employed [at the mass range of the high molecular weight (HMW) prolamins, error similar to 500 Da]. Two subunits, 1Dx2 and 1By9, however, showed M(r)s approximately 900 Da higher and 1700 Da lower, respectively, than expected from their gene sequences. These data confirm that the HMW subunits are not extensively glycosylated and also demonstrate the utility of mass spectrometry for determining the M(r)s of prolamins. (C) 1995 Academic Press Limited