The Phosphorus of Caseinogen

Abstract

From tryptic digests of caseinogen a P-containing peptone has been isolated in a pure state and in a yield representing 50% of the original organic P. This peptone, called "phosphopeptone, has the formula C37H62O33N9P33 and is a strongly acidic substance forming salts with 9 equivalents of Cu, Ba, Na, and brucine. It has [[alpha]][image] =80-53[degree]. One-ninth of the total N is amino N but after hydrolysis amino N= total N. The peptone is comparatively resistant to trypsin. From phosphopeptone were by hydrolysis obtained hydroxyglutamic acid, hydroxyaminobutyric acid, serine, and phosphoric acid. A structural formula has been constructed satisfying in all respects the chemical properties of phosphopeptone. Bone phospha-tase removes f and kidney phosphatase all of the P as phosphoric acid.