Ipomcein, a Globulin from Sweet Potatoes, Ipomcea Batatas Isolation of a Secondary Protein Derived from Ipomcein by Enzymic Action

As far as we are aware, there are no data in the literature relative to the proteins of sweet potatoes. Sweet potatoes rank second in importance as a truck crop in the United States and constitute one of the chief vegetable foods in the Southern States. Compared with other root vegetables they rank high in protein, the protein content ranging from 2 to 3.5 per cent. Sweet potatoes contain more true protein than do potatoes, although these two articles are usually represented ~t~i containing about the same percentages of crude protein (N X 6.25). About half of the nitrogen in potatoes does not represent protein, but is present largely in the form of amides. No amides have been found in sweet potatoes. The work described in this paper relates to the isolation and properties of a globulin which constitutes the greater part of the protein content of sweet potatoes. The composition and properties of another protein are described, which is formed from the original globulin by the action of proteolytic enzymes during the aging of the sweet potatoes at temperatures favorable to metabolic activity. When the juice or sodium chloride extract of recently harvested sweet potatoes, or of those which have been properly stored,’ is