The biological relations of seed proteins

Abstract

At a recent meeting of this society, Reichert and Brown gave the results of their examination of the crystal forms of hemoglobins obtained from a large number of different species of animals. 1

The crystallographic method was adopted because they believed that by this means they might succeed where the chemist had failed.

That the chemist has failed to establish differences between homologous proteins which are quite as marked as those indicated by the method employed by Reichert and Brown, I cannot admit.

Without wishing in any way to detract from the importance of the highly interesting results reported by Reichert and Brown, I would like to call your attention to the results obtained by purely chemical means in the investigations of the vegetable proteins which have been made in my laboratory during the past years, and which are in complete harmony with the results of Reichert and Brown.

The most marked instance of the agreement of both physical and chemical characteristics of the protein constituents of any group of seeds with the biological relations of the seeds is shown by the proteins of the cereals.

The seeds of the cereals are the only ones containing protein soluble in relatively strong alcohol. These proteins yield no lysine, much proline and ammonia, relatively little arginine and histidine, and, with the exception of that from the maize -which, however, yields nearly 20 per cent. -very large amounts of glutaminic acid. There is likewise a close resemblance between these seeds in the character and proportion of the several different forms of protein which they contain.

The proteins of the leguminous seeds are very much alike but very different froin those of the cereals. The proteins of the pea, horse bean, and lentil appear to differ from each other only in the proportion of their different forms, and from those of the vetch only in the absence of viciliri which is found in the other seeds.