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Sciencemadness Discussion Board » Special Topics » Biochemistry » Extracting plant proteins

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Contempt

Harmless

Posts: 6
Registered: 3-10-2005
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Mood: chilled

posted on 11-1-2006 at 23:10

Extracting plant proteins

Would this be considered an effective way of removing plant proteins from leaves or beans?

•Remove all oil from bean pulp

•Once dry add Filtrate (pulp powder) to blender with 4 times as much distilled water at a pH of 3.8 and a temperature of 25* C. Liquify for 15 Mins (Note: DILUTE HYDROCHLORIC ACID CAN be used for pH adjustment.)

•Filter Slurry using Filter and filter funnel and discard filtrate (The protein is now contained inside the acidic water)

•Raise the pH of this solution to pH 7, using 12% sodium Carbonate

•Treat the solution with a 16.7% solution of Sodium Sulphate (2 pounds of salt to 10 pounds of water) to precipitate the protein. Add a little at a time and cease additions when no more protein is precipitated. Allow up to 5 minutes between additions

•Filter solution and discard the liquid. Wash filtrate with some sodium sulphate solution to remove further nitrogen.

•The filtrate is dried and slurried with carbon tetrachloride to separate the protein by floatation

•The protein is then skimmed off the top

chemoleo

Biochemicus Energeticus

Posts: 3005
Registered: 23-7-2003
Location: England Germany
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Mood: crystalline

posted on 11-1-2006 at 23:52

It depends a little on the substance you are after (what is it??).

But yes, my first thought was ammonium sulphate precipitation.

I'd probably add a few steps.

Put it in blender, with a fair amount of water. Mesh it until its a homogenous mixture, and a bit longer, you want to break all those plant cell walls and nuclei.
Filter. Keep flowthrough. That should remove most of the proteins.
Then, concentrate the filtrate as far as you can, and add at least 4 M ammonium sulphate (final concentrtion) in the cold. Incubate, then filter or centrifuge. Nearly all of your protein should be gone. If your substance is EtOH, or acetone, or toluene-soluble, just gently extract it from the dried filtrate (warm slightly), and centrifuge it again.

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Sciencemadness Discussion Board » Special Topics » Biochemistry » Extracting plant proteins