Heptapeptide is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2026-04-15. Where a claim depends on a specific study, the study is described rather than over-claimed.
Lyophilised material kept dry at minus 20 degrees Celsius or colder is the most stable form, and suppliers commonly state a shelf life of two years or more under those conditions. Once dissolved, degradation accelerates through hydrolysis and deamidation, particularly at alkaline pH or elevated temperature. Working solutions are usually divided into single-use aliquots to avoid repeated freeze-thaw cycles. The choice of reconstitution solvent affects both stability and the ionic strength of the final preparation.
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres is the standard purity method. Mass spectrometry, typically electrospray ionisation, confirms identity through the expected mass-to-charge pattern. Amino acid analysis can verify composition independently. Chiral purity requires separate techniques such as derivatisation followed by chromatographic separation, and such data are rarely reported for research-grade material.
Quantification in biological matrices relies on liquid chromatography coupled to tandem mass spectrometry with stable-isotope internal standards. Low plasma concentrations and adsorption to container surfaces both complicate measurement. Solid-phase extraction is often needed to reduce matrix interference before injection. Reported limits of quantification differ widely between laboratories, which makes direct comparison of pharmacokinetic results difficult and limits meta-analysis.
Naming for this compound is not fully standardised in English sources. The spelling Selanc appears in some transliterations, and catalogue entries may instead list the peptide sequence itself as the identifier. Reference material sometimes groups it with other short synthetic peptides studied for behavioural effects, which can create confusion when citations are compared. Distinguishing the exact sequence from related tuftsin analogues is therefore a practical first step when reviewing any dataset or specification sheet.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, frequently abbreviated as TKPRPGP. It was designed as a structural analogue of tuftsin, a naturally occurring tetrapeptide released by enzymatic cleavage of the immunoglobulin heavy chain. The two additional proline residues at the C-terminal end extend the parent chain and change how the molecule behaves in solution. The free peptide has a calculated molecular mass of approximately 751.9 g/mol and is generally supplied as a lyophilised white to off-white powder.
| Property | Value | Notes |
|---|---|---|
| Dry storage temperature | -20 C or below | Sealed, desiccated, protected from light |
| Solution stability | Hours to days at 2-8 C | Depends on buffer and microbial load |
| Preferred pH range | Near neutral to slightly acidic | Alkaline pH accelerates hydrolysis |
| Main degradation routes | Hydrolysis and deamidation | No cysteine or methionine in sequence |
| Identity confirmation | Electrospray mass spectrometry | Observed mass compared with 751.9 Da |
Lyophilized material is generally stable for extended periods when kept dry at or below minus twenty degrees Celsius. Working solutions are less stable, and common practice is to aliquot and freeze them so that repeated freeze-thaw cycles are avoided. Aqueous solutions are sensitive to pH extremes and to microbial growth, so short-term storage at refrigerator temperature is typical. Oxidation and hydrolysis are the principal degradation routes. Reconstitution with sterile water or a mild buffer is standard, and solutions should be protected from light.
Regulatory treatment varies by jurisdiction. In Russia the compound is a registered prescription product, while in the European Union and the United States it is generally handled as a research chemical without a marketing authorization. Suppliers therefore operate outside pharmaceutical oversight, and buyers rely on supplier documentation for purity and identity claims. Chain of custody and third-party testing are the main verification tools. Analysts note that the absence of a pharmacopoeial monograph for research-grade material limits standardization across vendors.
Purity assessment relies mainly on reverse-phase high-performance liquid chromatography with ultraviolet detection. Because the peptide lacks a strong chromophore, detection often uses backbone absorbance near 214 nm. Identity is confirmed by mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, comparing the measured mass against the expected value. Amino acid analysis can verify composition after acid hydrolysis. Diastereomer content and residual counterions are reported less often, although both can influence biological assays.
Naming conventions place Selank in the same research family as Semax, another Russian-developed peptide investigated for cognitive effects. The two compounds share a lineage but differ in sequence and in the biological systems proposed as their targets. Semax descends from ACTH fragments, whereas Selank descends from tuftsin. Publications sometimes identify Selank by its full peptide sequence or by laboratory codes rather than one uniform trade name. Because replication outside Russia is limited, reports on its properties are best read alongside the study design and the purity of the material tested.
Selank is a synthetic heptapeptide developed in Russia during the 1990s. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences designed it as a stabilized analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The compound has been studied primarily for its reported anxiolytic and nootropic effects. It remains largely unknown in Western pharmacology and is not approved as a medicine by major regulators such as the FDA or the EMA.
== Function == GnSAF antagonises the positive feedback effects of estradiol on GnRH-induced LH release during the follicular phase. GnSAF inhibits the stimulatory role of estradiol in increasing GnRH-induced de novo synthesis of GnRH receptors in the pituitary. GnRH receptor mRNA levels are low in the presence of high GnSAF bioactivity, which limits the availability of binding sites for GnRH at the pituitary and decreased pituitary sensitivity to GnRH. The moderated GnRH pulse amplitude and frequency is sufficient for maintaining low blood concentrations of LH and protects against premature LH surges and LH hypersecretion. GnSAF also inhibits LH synthesis after the transcription stage and limits stored LH in the pituitary. Whilst the pulse amplitude of LH is reduced by GnSAF, constitutive production of LH is unaffected by GnSAF.
Distal stabilisation of muscles is often performed. This allows effective muscle contraction which reduces atrophy, allows functional use of the stump and maintains soft tissue coverage of the remnant bone. The preferred stabilisation technique is myodesis where the muscle is attached to the bone or its periosteum. In joint disarticulation amputations tenodesis may be used where the muscle tendon is attached to the bone. Muscles are attached under similar tension to normal physiological conditions. An experimental technique known as the "Ewing amputation" aims to improve post-amputation proprioception. Another technique with similar goals, which has been tested in a clinical trial, is Agonist-antagonist Myoneural Interface (AMI). In 1920, Dr. Janos Ertl Sr. of Hungary, developed the Ertl procedure in order to return a high number of amputees to the workforce. The Ertl technique, an osteomyoplastic procedure for transtibial amputation, can be used to create a highly functional residual limb. Creation of a tibiofibular bone bridge provides a stable, broad tibiofibular articulation that may be capable of some distal weight bearing. Several different modified techniques and fibular bridge fixation methods have been used; however, no current evidence exists regarding comparison of the different techniques.
=== Barcodes and digital links === Linear barcodes and two-dimensional symbols are used to identify packaged products and communicate data. QR codes can connect users to instructions, ingredient information, traceability records, authentication services, recall notices, and accessibility resources. The GS1 Digital Link standard defines how GS1 identifiers can be represented in web addresses and connected to online information and services. A printed barcode or QR code alone does not make a package active. It may be considered an intelligent or connected-packaging feature when it provides access to relevant data, uniquely identifies an item, records interactions, or operates with sensors and information systems. Digital identifiers can be copied unless they are combined with authentication, encryption, secure graphics, serialisation, or server-side verification.
== History == Food processing dates back to the prehistoric ages when crude processing incorporated fermenting, sun drying, preserving with salt, and various types of cooking (such as roasting, smoking, steaming, and oven baking), Such basic food processing involved chemical enzymatic changes to the basic structure of food in its natural form, as well served to build a barrier against surface microbial activity that caused rapid decay. Salt-preservation was especially common for foods that constituted warrior and sailors' diets until the introduction of canning methods. Evidence for the existence of these methods can be found in the writings of the ancient Greek, Chaldean, Egyptian and Roman civilizations as well as archaeological evidence from Europe, North and South America and Asia. These tried and tested processing techniques remained essentially the same until the advent of the Industrial Revolution. Examples of ready-meals also date back to before the preindustrial revolution, and include dishes such as Cornish pasty and Haggis. Both during ancient times and today in modern society these are considered processed foods.
=== EC 2.8.3: CoA-transferases === EC 2.8.3.1: propionate CoA-transferase EC 2.8.3.2: oxalate CoA-transferase EC 2.8.3.3: malonate CoA-transferase EC 2.8.3.4: deleted EC 2.8.3.5: 3-oxoacid CoA-transferase EC 2.8.3.6: 3-oxoadipate CoA-transferase EC 2.8.3.7: The activity is due to two enzymes, EC 2.8.3.22, succinyl-CoA—L-malate CoA-transferase and EC 2.8.3.20, succinyl-CoA—Dcitramalate CoA-transferase EC 2.8.3.8: acetate CoA-transferase EC 2.8.3.9: butyrate—acetoacetate CoA-transferase EC 2.8.3.10: citrate CoA-transferase EC 2.8.3.11: citramalate CoA-transferase EC 2.8.3.12: glutaconate CoA-transferase EC 2.8.3.13: succinate—hydroxymethylglutarate CoA-transferase EC 2.8.3.14: 5-hydroxypentanoate CoA-transferase EC 2.8.3.15: succinyl-CoA:(R)-benzylsuccinate CoA-transferase EC 2.8.3.16: formyl-CoA transferase EC 2.8.3.17: cinnamoyl-CoA:phenyllactate CoA-transferase EC 2.8.3.18: succinyl-CoA:acetate CoA-transferase EC 2.8.3.19: CoA:oxalate CoA-transferase EC 2.8.3.20: succinyl-CoA—D-citramalate CoA-transferase EC 2.8.3.21: L-carnitine CoA-transferase EC 2.8.3.22: succinyl-CoA—L-malate CoA-transferase EC 2.8.3.23: caffeate CoA-transferase EC 2.8.3.24: (''R'')-2-hydroxy-4-methylpentanoate CoA-transferase EC 2.8.3.25: bile acid CoA-transferase EC 2.8.3.26: succinyl-CoA:mesaconate CoA transferase
Sources: en.wikipedia.org
=== Hilary Wyndham === Hilary Wyndham (Mark Dexter) is a MD of the FX desk at Pierpoint. Throughout the first season, he is shown to be a more measured leader than his subordinate Kenny, an alcoholic and a bully who repeatedly subjects Yasmin to verbal abuse. However, nearing reduction-in-force (RIF) day, Hilary advises Yasmin not to report Kenny's behavior, telling her that being a "team player" would benefit her career prospects. Yasmin caves to Hilary's advice during her RIF interview when she denies having any negative experiences at Pierpoint, and Hilary vouches for her, ensuring that she is hired. In series 2, Hilary becomes paranoid about contracting COVID-19 at the office, wearing a mask to work and exhibiting germaphobe tendencies. Ironically, it is he who ends up falling ill and having to take time off from the office. Yasmin tells Hilary that she will be spending less time on the FX desk as she explores a move to the Private Wealth Management (PWM) division; Hilary, feeling numb and burnt out from the job, grants her his blessing. Hilary briefly reappears in series 4, now working for the Railways Pension Scheme (RPS); Eric calls him to invest in his and Harper's new short-only fund, SternTao, but Hilary kindly declines, stating that the RPS doesn't share their appetite for risk.
== Merchandising == The Guinness Storehouse at St. James's Gate Brewery in Dublin is the most popular tourist attraction in Ireland (attracting over 1.7 million visitors in 2019) where a self-guided tour includes an account of the ingredients used to make the stout and a description of how it is made. Visitors can sample the smells of each Guinness ingredient in the Tasting Rooms, which are coloured with a unique lighting design that emits Guinness's gold and black branding. The Guinness Book of Records started as a Guinness marketing giveaway, based on an idea of its then Managing Director, Sir Hugh Beaver. Its holding company, Guinness World Records Ltd, was owned by Guinness plc, subsequently Diageo, until 2001. The 2025 drama series House of Guinness deals with the growth of the business in 19th century Ireland.
The South Carolina Senate rejects a redistricting effort to eliminate the state's single majority-Black district, held by Democrat U.S. Representative Jim Clyburn, before the upcoming U.S. midterms. Joe Biden sues the DOJ to block the release of private audio recordings with his biographer Mark Zwonitzer for the 2017 memoir, Promise Me, Dad. The recordings were obtained during Special Counsel Robert Hur's probe into Biden's handling of classified documents after his vice presidency. The DOJ charges Michele Spagnuolo, a Google engineer, with breaking federal insider trading laws because of $2.7 million in bets related to Google he placed on Polymarket, a prediction market, between October and December 2025. May 27 The American Cancer Society announces that blood tests will be included for colorectal cancer screenings amidst a rise in colon cancer in young adults. The recommendations also reaffirm that screenings should begin at age 45. Former U.S. Attorney General Pam Bondi is diagnosed with thyroid cancer. CNN reports that the DOJ opened a criminal investigation into E. Jean Carroll, accusing her of perjury during her defamation and sexual abuse lawsuit against Trump. Meta launches paid subscriptions plans for Facebook, Instagram and WhatsApp. May 28 Axios reports that U.S. and Iran negotiators have reached a ceasefire extension deal, pending Trump's approval. At least three people are killed, four others are injured, and 11 more are reported missing in an explosion at an apartment building in Dallas, Texas.
The album was met with moderate commercial success and favorable reviews. Review aggregating website Metacritic reports a normalized score of 71% based on 7 reviews. Entertainment Weekly wrote that "the silky-voiced folk-popster successfully rocks up his sound on his fourth album, adding a polite but firm electric edge".
Sources: en.wikipedia.org
Dry powder is best kept sealed, protected from light, and held at minus 20 degrees Celsius or below. Desiccant packaging helps limit moisture uptake because the material is hygroscopic. A sealed vial should be allowed to equilibrate to room temperature before opening to reduce condensation.
Hydrolysis of peptide bonds and deamidation of arginine and proline residues are the main degradation routes. Alkaline pH and higher temperatures accelerate both processes. Buffered, near-neutral solutions stored cold generally degrade more slowly than unbuffered ones.
Reverse-phase chromatography gives the clearest single view of related impurities and truncated sequences. Mass spectrometry then confirms that the main peak carries the expected mass. Neither test detects enantiomeric impurities, which require a separate chiral assay.
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, commonly written as TKPRPGP. It shares the first four residues with tuftsin and carries three prolines in the chain. The proline-rich tail is the main structural feature that separates it from the parent tetrapeptide.