The following are multiple choice questions (with answers) about medical knowledge.   **Question:** Precipitation of proteins is done by all of these except:   (A) Adding trichloroacetic acid.   (B) Adding acetyl alcohol and acetone.   (C) Adjusting pH to other than the isoelectric point.   (D) Salts of heavy metals.
['(C) Adjusting pH to other than the isoelectric point. <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) Adding trichloroacetic acid. \n (B) Adding acetyl alcohol and acetone. \n (C) Adjusting pH to other than the isoelectric point. \n (D) Salts of heavy metals. <> possible answers', '  Precipitation of proteins is done by all of these except: <> context@']