PMID-sentid	Pub_year	Sent_text		comp_official_name	comp_offsetprotein_name	organism	prot_offset
2173185-5	1990	Substitution of the natural glycine residue by D-arginine residue in position 2 of the enkephalin molecule truncated at the C-terminus increased the mu-receptor binding potency of the tetrapeptide, whereas its delta receptor binding potency declined by more than one order of magnitude.	D-Arginine	47-57	proenkephalin	Rattus norvegicus	87-97