STUDIES ON PHOSPHORYLCHOLINE

¹ The Sir William Dunn Institute of Biochemistry, Cambridge, and the Sir William Dunn School of Pathology, Oxford

1. Phosphorylcholine has been synthesised from choline chloride and phosphorus pentoxide and isolated as the double salt OCH₂.CH₂.N(CH₃)₃+ 2AgNO₃.AgO—P—O-O

2. Phosphorylcholine, unlike most of the choline esters, is very stable towards alkaline and acid hydrolytic agents; this stability is attributed to the betaine structure of the compound.

3. Phosphorylcholine is hydrolysed by kidney, bone, and serum phosphatase.

4. The physiological properties of phosphorylcholine have been tested in the following ways: On the frog's heart, leech muscle, virgin guinea-pig's uterus, cat's blood-pressure and superior cervical ganglion, intestinal muscle of the rabbit, frog's rectus abdominus. In all cases its physiological activity was very slight, many thousand times less than the acetylcholine effect and sometimes qualitatively different from it. The physiological inertness of phosphorylcholine is again in accordance with its betaine structure.

We wish to express our gratitude to Professor Sir F. G. Hopkins and Professor H. W. Florey for hospitality and interest.