Phylogenetic relationship of zeins and coixins as determined by immunological cross-reactivity and Southern blot analysis

Abstract

Zeins from Zea mays L cv. Maya and coixins from Coix lacryma-jobi L. cv. Adlay were fractionated to obtain alpha-, beta-, and gamma-zein and alpha-, beta-, and gamma-coixin. The alpha-coixins were composed of 4 polypeptide classes of 27 kDa (C1), 25 kDa (C2), 17 kDa (C4) and 15 kDa (C5) with solubility properties very similar to those of the 22 kDa and 19 kDa alpha-zeins. Like the alpha-zeins, the C1 and C2 alpha-coixins corresponded to 80% of total Coix prolamins. The fraction corresponding to gamma-coixin contained only one protein band of 22 kDa (C3). This coixin fraction has solubility properties similar to those of gamma-zein and represents 15% of the total coixin. The beta-zein fraction was composed of a major 17 kDa protein band, while the beta-coixin fraction consisted of a mixture of alpha- and gamma-coixins. Polyclonal antibodies raised against C1 recognized C1 and C2 and cross-reacted strongly with the 22 kDa alpha-zein, as did C4 and C5 antisera. The antiserum against gamma-coixin showed strong cross-reaction with gamma-zein. The homology between coixins and zeins was further investigated by using Southern hybridization analyses. The genomic DNA of maize and Coix were digested with several restriction enzymes and probed with cDNA clones representing 19 and 22 kDa alpha-zeins as well as the 28 and 16 kDa gamma-zeins. The Coix genome showed complex cross-hybridization sequences with the 22 kDa alpha-zein cDNA, while no cross-hybridization was observed with the 19 kDa cDNA clone.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-diabetic Effects of Adlay Protein in Type 2 Diabetic db/db Mice

“…The major molecular classes observed in lane 2 were 27 kDa, 25 kDa, 22 kDa, 17 kDa and 15 kDa. This result demonstrates that the major protein in AP is a prolamine, by comparison with that of SDS-PAGE analysis for coixin, which belongs to the prolamine group, from adlay (Leite et al, 1990). AP contained proteins of more than 30 kDa, with the exception of prolamine.…”

The Major Seed Storage Proteins of Spelt Wheat, Sorghum, Millets and Pseudocereals

“…Both Coix and sorghum contain prolamins of Mr about 27,000-28,000 by SDS-PAGE whieh react with antibody to v-zein [20,24,34]. In addition, y-kafirin fractions from sorghum (Table 1.1) have been shown to have similar amino acid compositions to v-zeins [34].…”

“…However, the prolamins in the three species differ in their solubility properties indicating differences in sequence and structure whieh could affect their functional properties and utilization. The coOOns and zeins can be readily extracted with 55 vol.% aqueous propan-2-ol, in two sequential fractions differing in the absence or presence of a reducing agent such as 2-mercaptoethanol or dithiothreitol [19,20]. However, sorghum prolamins are more efficiently extracted using 60 vol.% aqueous tertiary butyl alcohol [21], a less polar solvent than 50 vol.% propan-2-ol.…”

The Prolamins of Sorghum, Coix and Millets

“…The seed protein contents of these tropical cereals range from 5 to 20%, and prolamins constitute the major seed storage proteins accounting for over 50% of the grain protein (Paulis and Wall, 1979;Okoh et al, 1985;Leite et al, 1990). Prolamins are given the trivial names of kafirins and coixins in sorghum and Coix, respectively.…”