A CA2-DEPENDENT PHOSPHORYLCHOLINE-BINDING PROTEIN IN CHICKEN SERUM()

A Ca2+-dependent phosphorylcholine (PC)-binding protein in normal chic ken serum was purified by affinity chromatography on p-aminophenyl PC- Sepharose 4B followed by gel filtration on Sephacryl S-300. In gel fil tration, the isolated PC-binding protein was eluted in a symmetrical p rotein peak at the position of approximately 100,000. On sodium dodecy l sulfate-polyacrylamide gel electrophoresis, the protein was resolved into two protein bands of 31,000 and 38,000 under nonreducing conditi ons and of 40,000 and 46,000 under reducing conditions. These results suggest that chicken serum PC-binding protein may be composed of two d ifferent subunits which contain intrachain disulfide bonds.