Purification and properties of the cyclic 3',5'-AMP-binding protein from the muscle of the Nematode Ascaris suum

The cyclic 3',5'-AMP-binding protein was isolated from the muscle of Ascaris suum and purified to apparent homogeneity. It migrated as a protein with a relative Mr 54,000 on electrophoresis under denaturing conditions. On gel filtration columns it was eluted at a volume corresponding to a protein of Mr greater than 200,000 under conditions which kept the cyclic 3',5'-AMP-binding property intact. The purified catalytic subunit of protein kinase from Ascaris and the C subunit of cyclic 3',5'-AMP-dependent protein kinase from bovine heart were inhibited by the cyclic 3',5'-AMP-binding protein. Gel filtration studies indicated the formation of a stable protein complex between the protein kinase and the cyclic 3',5'-AMP-binding protein from Ascaris.