Pentapeptides

An enkephalin is a pentapeptide involved in regulating nociception (pain sensation) in the body. The enkephalins are termed endogenous ligands, as they are internally derived (and therefore endogenous) and bind as ligands to the body's opioid receptors. Discovered in 1975, two forms of enkephalin have been found, one containing leucine ("leu"), and the other containing methionine ("met"). Both are products of the proenkephalin gene: Met-enkephalin is Tyr-Gly-Gly-Phe-Met. Leu-enkephalin is Tyr-Gly-Gly-Phe-Leu.

Viomycin is a member of the tuberactinomycin family, a group of nonribosomal peptide antibiotics exhibiting anti-tuberculosis activity. The tuberactinomycin family is an essential component in the drug cocktail currently used to fight infections of Mycobacterium tuberculosis. Viomycin was the first member of the tuberactinomycins to be isolated and identified, and was used to treat TB until it was replaced by the less toxic, but structurally related compound, capreomycin. The tuberactinomycins target bacterial ribosomes, binding RNA and disrupting bacterial protein synthesis and certain forms

drug for volume regulation

Met-enkephalin, also known as metenkefalin (INN), sometimes referred to as opioid growth factor (OGF), is a naturally occurring, endogenous opioid peptide that has opioid effects of a relatively short duration. It is one of the two forms of enkephalin, the other being leu-enkephalin. The enkephalins are considered to be the primary endogenous ligands of the δ-opioid receptor, due to their high potency and selectivity for the site over the other endogenous opioids.

Enterostatin is a pentapeptide derived from a proenzyme in the gastrointestinal tract called procolipase. It reduces food intake, in particular fat intake, when given peripherally or into the brain.

Nemifitide (INN-00835) is a novel antidepressant drug with a pentapeptide structure similar to that of melanocyte-inhibiting factor (MIF-1) and the amino acid sequence 4-F-Phe-4-OH-Pro-Arg-Gly-Trp-NH2. It is under development by Tetragenex (previously Innapharma, Inc.) for the treatment of major depressive disorder. It has been given to over 430 people over the course of 12 clinical trials throughout a little over the past decade and has reached Phase III studies, but has not yet been approved for marketing in any country.

Thymopentin is a thymic polypeptide derivative which interacts with T cells and acts as an immunostimulant. As such, it was used in several clinical studies in the early years of the AIDS pandemic (from 1983 to 1985). Thymopentin helped to improve immunological condition in some patients for a brief time under specific treatments. It has also been investigated more recently for applications in the treatment of rheumatoid arthritis, and lung cancer.

BQ-123, also known as cyclo(-D-Trp-D-Asp-Pro-D-Val-Leu-), is a cyclic pentapeptide that was first isolated from a fermentation broth of Streptomyces misakiensis in 1991. NMR studies indicate that the polypeptide backbone consists of a type II beta turn and an inverse gamma turn. The side-chains adopt different orientations depending on the solvent used. The proline carbonyl oxygen atom located at the onset of a beta turn is a sodium ion binding site. It has a high affinity for sodium ions and can coordinate up to three of them. Studies have shown that BQ123 is effective in reversing Ischemia-i