Citric Acid → Citrate phosphate

Participants

Reaction Steps

A citrate-phosphate buffer (pH 3.0) was prepared from 39.8 ml of 0.1 M citric acid and 10.2 ml of 0.2 M dibasic sodium phosphate diluted to 100 ml with distilled water. The lyophilized Fraction A from Preparation 1 was dissolved in this buffer solution in a proportion of 20 mg of Fraction A per ml of buffer. To this was added an aliquot of 5 mg of pepsin in 1 ml of distilled water to give a ratio of Fraction A to pepsin of 100 to 1. The solution was maintained for 24 hours at room temperature and then brought to pH 7.4 by the addition of 0.1 M sodium hydroxide. The resulting product was the crude ragweed polypeptide active immunosuppressant fraction.

Provenance & Evidence