1) Institute of Agronomy, National Taiway University, Roosevelt Road, Taipei
2) Institute of Botany, Academia Sinica, Nankang, Taipei, Taiwan, ROC
Glutelin is the major storage protein of rice and is processed post-
translationally from 57 KD precursor into the alpha and beta subunits with
molecular weight 37-39 KD and 21-22 KD, respectively (Yamagata et al. 1982). By
isoelectric focusing, it can also be dissolved into groups of acidic and basic
bands that correspond to the alpha and beta subunits, respectively. The acidic
bands were separated into several bands (Wen and Luthe 1985). The two-
dimensional separation of the alpha subunit of glutelin from 13 genomic species
of Oryza is reported in this note. It revealed That in the species examined
there were a number of different polypeptides that were heterogeneous in both
molecular weight and isoelectric point (pI value), as shown in Fig. 1 and Table
1. Polypeptides with 20/7.5, 30/7.3 and 30/7.1, which were found in most
species may be considered as the main constitutive. Thus, similarity and
diversity in glutelin alpha subunit were disclosed among Oryza species.
Table 1. Constitutive polypeptides of glutelin a(alpha) subunit as
designated by molecular weight (numerator) and pI value (deonominator) in Oryza
species with different genomes
Fig. 1. Two-dimensional separation of glutelin a(alpha) subunit.
Verticial axis represents molecular weight (e.g., 32.5, 31.0, 30.0, and 29.9
KD from upper to lower point for Taichung 65). Dots along the horizontal axis
indicates pI value (e.g., 7.60, 7.50, 7.30, 7.10, 6.80, 6.70 and 6.50 from left
to right for Taichung 65).
References
Wen, T.N. and D.S. Luthe, 1985. Biochemical characterization of rice glutelin. Plant Physiol. 78: 172.
Yamagata, H., K. Tanaka and Z. Kasai, 1982. Biosynthesis of storage proteins in developing rice seeds. Plant Physiol. 70: 1094.