Phosphorylation of Proteins

Abstract

Proteins may be phosphorized by means of phosphorous oxychloride dissolved in CCl4 in a manner analogous to the Schotten-Baumann reaction. The phosphorized products obtained from caseinogen, serum globulin (horse), and dephosphorized caseinogen contain respectively 1.77, 0.71, and 1.75% P. Trypsin attacks phosphorized globulin in a manner analogous to its action on caseinogen. An arid-soluble substance is liberated containing all the P in organic combination and from this the P is rapidly and quantitatively removed as phosphoric acid by the action of bone phos-phatase. The nature of the P linkage in caseinogen and in these phosphorized products is discussed.