Abstract
The
two major subunits of rice glutelin, the acidic (α) and basic (β)
polypeptides were purified by chromatofocusing and cation exchange
chromatography, respectively. The molecular weight range of the α
polypeptides was 28.5 to 30.8 kilodaltons and the molecular weight range
of the β polypeptides was 20.6 to 21.6 kilodaltons. Electrofocusing in
polyacrylamide gels showed that the isoelectric points of the α and β
polypeptides were 6.5 to 7.5 and 9.4 to 10.3, respectively.
At least 12
polypeptides of the α-group and nine polypeptides of the β-group could
be separated by electrofocusing. The amino acid compositions of whole
glutelin, and the purified α and β subunits were analyzed.
The α subunit
contained more glutamic acid/glutamine (E/Q) , serine (S) , and glycine (G), and less
alanine (A), lysine (K), aspartic acid/asparagine (D/N), and isoleucine (I) than the β
subunit. A comparison of the amino acid composition of rice glutelin
subunits with those of the 11S proteins from eight other plant species
indicated that there is more similarity between the β subunits than the α
subunits of several diverse plant species.
Inga kommentarer:
Skicka en kommentar