A tripeptide is a

peptide Peptides (, ) are short chains of amino acids linked by peptide bonds. Long chains of amino acids are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides. A ...

derived from three

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha am ...

s joined by two or sometimes three

peptide bond In organic chemistry, a peptide bond is an amide type of covalent chemical bond linking two consecutive alpha-amino acids from C1 (carbon number one) of one alpha-amino acid and N2 (nitrogen number two) of another, along a peptide or protein cha ...

s. As for proteins, the function of peptides is determined by the constituent amino acids and their sequence. The simplest tripeptide is glycine. In terms of scientific investigations, the dominant tripeptide is

glutathione Glutathione (GSH, ) is an antioxidant in plants, animals, fungi, and some bacteria and archaea. Glutathione is capable of preventing damage to important cellular components caused by sources such as reactive oxygen species, free radicals, pe ...

(γ-L-Glutamyl-L-cysteinylglycine), which serves many roles in many forms of life.

Examples

* Eisenin (pGlu-Gln-Ala-OH) is a peptide with immunological activity that is isolated from the Japanese marine alga, ''Eisenia bicyclis'', which more commonly is known as

Arame , sea oak is a species of kelp, of the brown algae, best known for its use in Japanese cuisine. Description ''Eisenia bicyclis'' is indigenous to temperate Pacific Ocean waters centered near Japan, although it is deliberately cultured elsewh ...

* GHK-Cu (glycyl-L-histidyl-L-lysine) is a human copper binding peptide with wound healing and skin remodeling activity, which is used in anti-aging cosmetics and more commonly referred to as copper peptide *

Lactotripeptides Lactotripeptides are two naturally occurring milk peptides: Isoleucine-Proline-Proline (IPP) and Valine-Proline-Proline (VPP). These lactotripeptides are derived from casein, which is a milk protein also found in dairy products. Although most norma ...

(Ile-Pro-Pro and Val-Pro-Pro) found in milk products, act as ACE inhibitors *

Leupeptin Leupeptin, also known as ''N''-acetyl-L-leucyl-L-leucyl-L-argininal, is a naturally occurring protease inhibitor that can inhibit cysteine, serine and threonine peptidases. It is often used during ''in vitro'' experiments when a specific enzymati ...

(''N''-acetyl-L-leucyl-L-leucyl-L-argininal) is a protease inhibitor that also acts as an inhibitor of

calpain A calpain (; , ) is a protein belonging to the family of calcium-dependent, non-lysosomal cysteine proteases ( proteolytic enzymes) expressed ubiquitously in mammals and many other organisms. Calpains constitute the C2 family of protease clan C ...

Melanostatin Melanocyte-inhibiting factor (also known as Proline, Pro-Leucine, Leu-Glycine, Gly-NH2, Melanostatin, MSH release–inhibiting hormone or MIF-1) is an endogenous peptide fragment derived from cleavage of the hormone oxytocin, but having generally ...

(prolyl-leucyl-glycinamide) is a peptide hormone produced in the

hypothalamus The hypothalamus () is a part of the brain that contains a number of small nuclei with a variety of functions. One of the most important functions is to link the nervous system to the endocrine system via the pituitary gland. The hypothalamu ...

that inhibits the release of

melanocyte-stimulating hormone The melanocyte-stimulating hormones, known collectively as MSH, also known as melanotropins or intermedins, are a family of peptide hormones and neuropeptides consisting of α-melanocyte-stimulating hormone (α-MSH), β-melanocyte-stimulating ...

(MSH) *

Ophthalmic acid Ophthalmic acid, also known as ophthalmate (chemically L-γ-glutamyl-L-α-aminobutyrylglycine), is a tripeptide analog of glutathione in which the cysteine group is replaced by L-2-aminobutyrate. It was first discovered and isolated from calf len ...

(L-''γ''-glutamyl-L-''α''-aminobutyryl-glycine) is an analogue of glutathione isolated from

crystalline lens The lens, or crystalline lens, is a transparent biconvex structure in the eye that, along with the cornea, helps to refract light to be focused on the retina. By changing shape, it functions to change the focal length of the eye so that it ca ...

* Norophthalmic acid (''y''-glutamyl-alanyl-glycine) is an analogue of glutathione (L-cysteine replaced by L-alanine) isolated from

Thyrotropin-releasing hormone Thyrotropin-releasing hormone (TRH) is a hypophysiotropic hormone produced by neurons in the hypothalamus that stimulates the release of thyroid-stimulating hormone (TSH) and prolactin from the anterior pituitary. TRH has been used clinicall ...

(TRH, thyroliberin or protirelin) (L-pyroglutamyl-L-histidinyl-L-prolinamide) is a

peptide hormone Peptide hormones or protein hormones are hormones whose molecules are peptide, or proteins, respectively. The latter have longer amino acid chain lengths than the former. These hormones have an effect on the endocrine system of animals, including h ...

that stimulates the release of

thyroid-stimulating hormone Thyroid-stimulating hormone (also known as thyrotropin, thyrotropic hormone, or abbreviated TSH) is a pituitary hormone that stimulates the thyroid gland to produce thyroxine (T4), and then triiodothyronine (T3) which stimulates the metabolism of ...

and

prolactin Prolactin (PRL), also known as lactotropin, is a protein best known for its role in enabling mammals to produce milk. It is influential in over 300 separate processes in various vertebrates, including humans. Prolactin is secreted from the pit ...

by the

anterior pituitary A major organ of the endocrine system, the anterior pituitary (also called the adenohypophysis or pars anterior) is the glandular, anterior lobe that together with the posterior lobe (posterior pituitary, or the neurohypophysis) makes up the p ...

*ACV (δ-(L-α-aminoadipyl)-L-Cys-D-Val) is a key

biosynthetic Biosynthesis is a multi-step, enzyme-Catalysis, catalyzed process where substrate (chemistry), substrates are converted into more complex Product (chemistry), products in living organisms. In biosynthesis, simple Chemical compound, compounds are mo ...

precursor to

penicillin Penicillins (P, PCN or PEN) are a group of β-lactam antibiotics originally obtained from ''Penicillium'' moulds, principally '' P. chrysogenum'' and '' P. rubens''. Most penicillins in clinical use are synthesised by P. chrysogenum using ...

and

cephalosporin The cephalosporins (sg. ) are a class of β-lactam antibiotics originally derived from the fungus ''Acremonium'', which was previously known as ''Cephalosporium''. Together with cephamycins, they constitute a subgroup of β-lactam antibiotics ...

References

Peptides Tripeptides {{Protein-stub

Examples

See also

References