Preparation and crystallization of Fraction I protein from plant sources

A method for preparing ribulose 1,5-bisphosphate carboxylase (RuBisCO) from plant material, said method comprising:

• comminuting the plant material in an aqueous solution to form a suspension;
• fractionating said suspension to release the RuBisCO from the ground plant material into the solution;
• and
• adding a sufficient amount of polyethylene glycol (PEG) to the solution so that crystals of RuBisCO are selectively formed;
• separating the crystals from the solution;
• redissolving the crystals in substantially pure water;
• and
• passing the redissolved crystals through an anionic resin bed in the presence of a divalent metal ion at a concentration sufficient to prevent the binding of RuBisCO to the resin.

A method for preparing ribulose 1,5-bisphosphate carboxylase (RuBisCO) from plant material, said method comprising:

• comminuting the plant material in an aqueous solution to form a suspension;
• fractionating said suspension to release the RuBisCO from the comminuted plant material into the solution;
• separating the remaining plant material from the solution to form a supernatant;
• passing the supernatant through an anionic resin bed so that at least the RuBisCO binds to said resin;
• washing the resin bed to remove unbound material;
• and
• passing a solution including divalent metal ion through the resin bed to specifically elute the RuBisCO from the resin.

A method for preparing ribulose 1,5-bisphosphate carboxylase (RuBisCO) from plant material, said method comprising:

• comminuting the plant material in an aqueous solution to form a suspension;
• fractionating said suspension to release the RuBisCO and proteinaceous contaminants from the comminuted plant material into the solution;
• separating the remaining plant material from the solution to form a supernatant including the RuBisCO and at least some of said dissolved contaminants;
• passing the supernatant through an anionic resin bed in the presence of a divalent metal ion at a concentration selected so that substantially all of the contaminants bind to resin while the RuBisCO is prevented from binding to said resin.