CELL-WALL PROTEINS IN SEEDLING COTYLEDONS OF PROSOPIS-CHILENSIS

Four cell wall proteins of cotyledons of Prosopis chilensis seedlings were characterized by PAGE and Western analyses using a polyclonal ant ibody, generated against soybean seed coat extensin. These proteins ha d M(r)s of 180 000, 126 000, 107 000 and 63 000, as determined by SDS- PAGE. The proteins exhibited a fluorescent positive reaction with dans ylhydrazine suggesting that they are glycoproteins; they did not show peroxidase activity. The cell wall proteins were also characterized by their amino acid composition and by their amino-terminal sequence. Th ese analyses revealed that there are two groups of related cell wall p roteins in the cotyledons. The first group comprises the proteins of M (r)s 180 000, 126 000, 107 000 which are rich in glutamic acid/ glutam ine and aspartic acid/asparagine and they have almost identical NH2-te rminal sequences. The second group comprises the M(r) 63 000 protein w hich is rich in proline, glycine, valine and tyrosine, with an NH2-ter minal sequence which was very similar to that of soybean proline-rich proteins.