1. Efficient Fmoc/solid-phase peptide synthesis of O-phosphotyrosyl-containing peptides and their use as phosphatase substrates
J W Perich, M Ruzzene, L A Pinna, E C Reynolds Int J Pept Protein Res. 1994 Jan;43(1):39-46. doi: 10.1111/j.1399-3011.1994.tb00374.x.
A general synthetic method for the efficient preparation of Tyr(P)-containing peptides is described by the use of Fmoc-Tyr(PO3tBu2)-OH in Fmoc/solid-phase synthesis followed by simultaneous cleavage of the peptide from the resin and peptide deprotection by acidolytic treatment. The applicability of this approach is demonstrated by the synthesis of H-Ser-Ser-Ser-Tyr(P)-Tyr(P)-OH.TFA and the synthesis of the phosphorylated forms of the two physiological peptides, angiotensin II and neurotensin 8-13. In addition, the three phosphorylated peptides were used as substrates in the study of the local specificity determinants of T-cell protein tyrosine phosphatase. In a competition assay using 32P-radiolabeled [Tyr(P)]4-angiotensin II, both unlabeled synthetic [Tyr(P)]4-angiotensin II and Ser-Ser-Ser-Tyr(P)-Tyr(P) reduced the release of 32P and indicated that they efficiently competed as substrates for the phosphatase. Conversely, [Tyr(P)]4-neurotensin 8-13 was ineffective as a competitive substrate and indicated that this particular Tyr(P)-containing peptide sequence was not recognized by the enzyme. The marked difference in the recognition of Asp-Arg-Val-Tyr(P)-Ile-His-Pro-Phe and Arg-Arg-Pro-Tyr(P)-Ile-Leu is consistent with the presence of an acidic residue in the -3 position relative to the Tyr(P) residue.
2. The amino acid sequence of a smooth muscle-contracting peptide from chicken rectum. Identity to chicken neurotensin
H Iwabuchi, S Komori, H Ohashi, S Kimura Jpn J Pharmacol. 1987 Aug;44(4):455-9. doi: 10.1254/jjp.44.455.
Previous studies have demonstrated that chicken rectum contains a peptide which exerts a potent, excitatory action on the smooth muscle of chicken rectum, and this peptide is most likely to be chicken neurotensin isolated recently from chicken small intestine. In the present study, the peptide was extracted from 2 kg of chicken rectums, and then it was isolated by gel filtration, ion exchange chromatography, high voltage paper electrophoresis and HPLC. Amino acid analysis of the peptide revealed that it is a tridecapeptide composed of aspartic acid (Asp), glutamic acid (Glu), proline (Pro), alanine (Ala), valine (Val), isoleucine (Ile), two residues of leucine (Leu), tyrosine (Tyr), histidine (His), lysine (Lys) and two residues of arginine (Arg). Its amino acid sequence was determined to be pGlu-Leu-His-Val-Asn-Lys-Ala-Arg-Arg-Pro-Tyr-Ile-Leu-OH. The molecule is identical to chicken neurotensin.
3. Neurotensin: peptide for the next millennium
B M Tyler-McMahon, M Boules, E Richelson Regul Pept. 2000 Sep 25;93(1-3):125-36. doi: 10.1016/s0167-0115(00)00183-x.
Neurotensin is an endogenous tridecapeptide neurotransmitter (pGlu-Leu-Tyr-Glu-Asn-Lys-Pro-Arg-Arg-Pro-Try-Ile-Leu-OH) that was discovered by Carraway and Leeman in bovine hypothalami in the early 1970s. Since then this peptide has been the subject of a multitude of articles detailing discoveries related to its activity, receptors, localization, synthesis, and interactions with other systems. This review article does not intend to summarize again all the history of this fascinating peptide and its receptors, since this has been done quite well by others. The reader will be directed to these other reviews, where appropriate. Instead, this review attempts to provide a summary of current knowledge about neurotensin, why it is an important peptide to study, and where the field is heading. Special emphasis is placed on the behavioral studies, particularly with reference to agonists, antagonists, and antisense studies, as well as, the interaction of neurotensin with other neurotransmitters.
