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

High molecular weight (HMW) subunits of glutenin, corresponding to tho se for which full length gene sequences are available, were purified a nd 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 5 00 Da]. Two subunits, 1Dx2 and 1By9, however, showed M(r)s approximate ly 900 Da higher and 1700 Da lower, respectively, than expected from t heir gene sequences. These data confirm that the HMW subunits are not extensively glycosylated and also demonstrate the utility of mass spec trometry for determining the M(r)s of prolamins. (C) 1995 Academic Pre ss Limited