Expression and Cell Type—Specific Processing of Human Preproenkephalin with a Vaccinia Recombinant

The posttranslational maturation of a complex precursor polyprotein, human proenkephalin, was assessed by infection of a wide spectrum of cell types with a recombinant vaccinia virus that expressed human proenkephalin. The infected cells rapidly produced both cellular and secreted Met-enkephalin immunoreactivity. Although each cell line could secrete intact proenkephalin, only a mouse pituitary line was capable of processing proenkephalin to mature enkephalin peptides. The quantity of intact proenkephalin secreted from BSC-40 cells (derived from African Green monkey kidney) was sufficient to establish the value of vaccinia virus as a mammalian cell expression vector.