The Extraction, Composition and Intra‐cellular Distribution of Protein in Early Maize Grains From an Archaeological Site in N.E. Arizona

Abstract

Maize grains from an archaeological site in N.E. Arizona have been examined by light microscopy and electron microscopy. Their endosperm tissue was intact and was similar to that of modern maize although some of the features seen in other non-viable seeds were present; the embryos, however, were discoloured and damaged. Protein has been extracted from both endosperm and embryos although only a small quantity was extracted from the latter. The protein sub-unit profiles of these extracts and of storage protein fractions prepared by serial extraction of endosperm meal in salt, alcohol and sodium dodecyl sulphate (SDS) solutions have been determined after electrophoresis in SDS-acrylamide gels. The data obtained indicate that zein and glutelins similar to modern maize proteins were the major storage proteins but that their proportions differed to those in modern maizes; these conclusions are supported by the amino acid composition of the wholse seed meal. It is suggested that these procedures may be applicable to other archaeological samples of seeds including those of other species and that the data so obtained may be of use in cultural studies and in botanical studies of crop plant origins and evolution.

A Comparison of the Protein and Amino Acid Composition of Old and Recent Barley Grain

“…There were, however, some differences, notably low lysine in the three Egyptian barleys and low methionine in the two oldest samples. These results agree with those of Derbyshire et al (1977) who analyzed maize grain dating from at least 700 years ago. We also showed, however, that there were reduced proportions of arginine and glycine in the two oldest samples only.…”

“…We were, unfortunately, unable to obtain old barley grain to confirm this observation. In contrast Derbyshire et al (1977) reported the presence of zein (storage protein) and glutelin-type proteins in maize grain dating from before 1300 A.D. It is possible that in this case the proteins were preserved for an unusually long period by the conditions of storage.…”

“…The irregular shape of the bodies is characteristic of mature barley grain and results from their being squashed between the starch grain during the later stages of grain-fllling and dehydration. Derbyshire et al (1977) also reported the presence of numerous protein bodies in their old maize grain, although in this case they contained proteins recognizable as zein, the prolamin storage protein in this cereal. The protein bodies in our old grain probably contained a mixture of partially degraded proteins.…”

“…Chemical analysis of such samples of barley and other cereal grain are also rare and the results contradictory. Zeven, Doekes and Kislev (1975) estimated that the maximum age for the demonstration of most types of protein in wheat seeds was between 125 and 175 years, but Derbyshire et al (1977) reported the extraction and separation of protein fractions from maize grain dating from at least 700 years ago. The only chemical analysis reported for barley is that of Barton-Wright, Booth and Pringle (1944) who demonstrated the presence of riboflavin and nicotinic acid m carbonized grain from Tutankhamen's tomb (about 3300 years ago).…”

“…The only chemical analysis reported for barley is that of Barton-Wright, Booth and Pringle (1944) who demonstrated the presence of riboflavin and nicotinic acid m carbonized grain from Tutankhamen's tomb (about 3300 years ago). So the suggestion by Derbyshire et al (1977) that protein analysis might be a useful criterion for archaeological studies and investigations of plant origin and evolution may sometimes be true.…”