The neurohypophysial peptide oxytocin (OT) and OT-like hormones facilitate reproduction in all vertebrates at several levels. The major site of OT gene expression is the magnocellular neurons of the hypothalamic paraventricular and supraoptic nuclei. In response to a variety of stimuli such as suckling, parturition, or certain kinds of stress, the processed OT peptide is released from the posterior pituitary into the systemic circulation. Such stimuli also lead to an intranuclear release of OT. Moreover, oxytocinergic neurons display widespread projections throughout the central nervous system. However, OT is also synthesized in peripheral tissues, e.g., uterus, placenta, amnion, corpus luteum, testis, and heart. The OT receptor is a typical class I G protein-coupled receptor that is primarily coupled via Gq proteins to phospholipase C-β. The high-affinity receptor state requires both Mg2+ and cholesterol, which probably function as allosteric modulators. The agonist-binding region of the receptor has bee...

The Oxytocin Receptor System: Structure, Function, and Regulation

9-Fluorenylmethoxycarbonyl (Fmoc) amino acids were first used for solid phase peptide synthesis a little more than a decade ago. Since that time, Fmoc solid phase peptide synthesis methodology has been greatly enhanced by the introduction of a variety of solid supports, linkages, and side chain protecting groups, as well as by increased understanding of solvation conditions. These advances have led to many impressive syntheses, such as those of biologically active and isotopically labeled peptides and small proteins. The great variety of conditions under which Fmoc solid phase peptide synthesis may be carried out represents a truly "orthogonal" scheme, and thus offers many unique opportunities for bioorganic chemistry.

Solid phase peptide synthesis utilizing 9‐fluorenylmethoxycarbonyl amino acids

The reaction of acetylcholine and other carboxylic acid derivatives with hydroxylamine, and its analytical application.

The oxidation of ribonuclease with performic acid.

The proteins, as the Greek root of their name implies, are of first rank in living systems, and their smaller relatives, the peptides, have now also been discovered to have important roles in biology. Among their members are many of the hormones, releasing factors, growth factors, ion carriers, antibiotics, toxins, and neuropeptides. My purpose today is to describe the chemical synthesis of peptides and proteins and to discuss the use of the synthetic approach to answer various biological questions. The story begins with Emil Fischer (1) at the turn of this century when he synthesized the first peptide and coined the name. The general chemical requirements were to block the carboxyl group of one amino acid and the amino group of the second amino acid. Then, by activation of the free carboxyl group the peptide bond could be formed, and selective removal of the two protecting groups would lead to the free dipeptide. Fischer himself was never able to find a suitable reversible blocking group for the amine function, but his former student Max Bergmann, with Zervas, was successful (2). Their design of the carbobenzoxy group ushered in a new era. When I began working on the synthesis of peptides many years later this same general scheme was universally in use and was very effective, having led, for example, to the first synthesis of a peptide hormone by Du Vigneaud in 1953 (3). It soon became clear to me, however, that such syntheses were difficult and time consuming and that a new approach was needed if large numbers of peptides were required or if larger and more complex peptides were to be made.

http://science.sciencemag.org/content/sci/232/4748/341.full.pdf

Vincent du Vigneaud

Papers

The synthesis of an octapeptide amide with the hormonal activity of oxytocin

A Method of Synthesis of Long Peptide Chains Using a Synthesis of Oxytocin as an Example

The sequence of amino acids in oxytocin, with a proposal for the structure of oxytocin.

The Synthesis of Oxytocin1

Enzymatic cleavage of glycinamide from vasopressin and a proposed structure for this pressor-antidiuretic hormone of the posterior pituitary