An expression system has been designed for the rapid and economic expression of recombinant neurotensin for biophysical studies. A synthetic gene for neurotensin (Glu(1)-Leu(2)-Tyr(3)-Glu(4)-Asn(5)-Lys(6)-Pro(7)-Arg(8)-Arg(9)-Pro(10)-Tyr(11)-Ile(12)-Leu(13)) was cloned into the pGEX-5X-2 vector to allow expression of neurotensin as a glutathione S-transferase (GST) fusion protein. The inclusion of a methionine residue between. the glutathione S-transferase and the neurotensin has facilitated the rapid cleavage of the neurotensin from its carrier protein, Purification of recombinant neurotensin was performed by reverse-phase HPLC, This method produced a relatively high yield of peptide and offers the potential for economic partial or uniform labeling of small peptides (<15 amino acids) with isotopes for NMR or other biophysical techniques.