Abstract: Described herein is a process for isolating the enzymatic protein ribulose 1,5-diphosphate carboxylase from the green leaves of plants. In the process, which is particularly suited to obtaining the protein from tobacco, the leaves are ground or otherwise pulverized in the presence of a reducing agent. A liquid portion containing the desired protein is separated from the pulp and its pH adjusted to within the range of from about pH 6.0 to 5.3 and then cooled to cause the crystallization of the ribulose 1,5-diphosphate carboxylase. After separation of the crystalline material, the supernatant is acidified to yield lower molecular weight proteins.

Abstract: Described herein is a process for obtaining a smoking product from tobacco leaves. The leaves, or leaves and stalk together when immature plants are used in the process, are ground or otherwise pulverized to liberate the liquid portion of the leaves from the plant material. The liquid portion of the leaves is treated to remove water-soluble proteins and nicotine and the solid portion of the leaves is treated to remove water and insoluble protein material, nicotine and green pigment material. The residues obtained after separation of the water-soluble and -insoluble protein, nicotine and green pigment material are recombined to yield a processed tobacco which is suitable for use in cigarettes as a tobacco filler or other products of tobacco manufacture.

Abstract: Described herein is a process for isolating the enzymatic protein ribulose 1,5-diphosphate carboxylase from the green leaves of plants. In the process, which is particularly suited to obtaining the protein from tobacco, the leaves are ground or otherwise pulverized in the presence of a reducing agent, followed by heating the resulting pulp to about 50.degree. C. A liquid portion containing the desired protein is separated from the pulp and then cooled to cause the crystallization of the ribulose 1,5-diphosphate carboxylase. After separation of the crystalline material, the supernatant is acidified to yield lower molecular weight proteins.