Isolation and structural organization of the human preproenkephalin B gene

The primary structure of porcine preproenkephalin B has been elucidated by cloning and sequencing cDNA: it contains neoendorphin, dynorphin and leumorphin (containing rimorphin as its amino-terminus). These opioid peptides, each having a leucine-enkephalin structure, act on the kappa-receptor. We have now cloned a human genomic DNA segment containing the preproenkephalin B gene. The structural organization of this gene resembles those of the genes encoding the other opioid peptide precursors, that is, preproenkephalin A and the corticotropin-beta-lipotropin precursor (ACTH-beta-LPH precursor). The primary structure of human preproenkephalin B has been deduced from the gene sequence. The amino acid sequence homology observed between preproenkephalin B and preproenkephalin A, together with the similarity between their gene organizations, suggests that the two genes have been generated from a common ancestor by gene duplication.