Accumulation of seed storage proteins in Cleome gynandra L. and Brassica kaber L.

Seed proteins of Cleome gynandra were characterised and compared with wild mustard (Brassica kaber) seed proteins. Proteins were extracted, analysed with SDS-PAGE and sequenced. The gels were stained with standard Coomassie blue and bands were determined with Quantity One computer package. Prominent protein bands were present at Mr 40–48 kDa, 25–28 kDa and 15 kDa in the unreduced seed samples of C. gynandra. On reduction with DTT, the gels showed high intensity bands at Mr 27–28 kDa, 18–20 kDa and 13–15 kDa. Two-dimensional SDS-PAGE showed that the polypeptides of Mr 27–30 kDa occurred at pI 6.5–7.5 and the polypeptides of Mr 18–20 kDa were present at pI 8.5–9.6. The seed proteins diminished during radicle protrusion and this suggests that they are storage proteins. Comparison with proteins in the proteome library and similarity index further showed that the seed proteins of Cleome had similarities with those of wild mustard. Two-dimensional SDS-PAGE showed that the two species have nine similar polypeptides and that B. kaber has four additional polypeptides.