heptapeptide comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2025-10-03. Where a claim depends on a specific study, the study is described rather than over-claimed.
Regulatory status differs sharply by region. Selank holds a Russian marketing authorization, where it is supplied mainly as nasal drops, while authorities elsewhere have not approved it for medical use. Material sold internationally is therefore usually labeled as a research chemical rather than a medicine. Peer-reviewed publications come predominantly from Russian laboratories, and sample sizes are generally small. Whether the compound produces comparable effects under independent, well-controlled replication remains an open question that the broader literature has not settled.
Selank is a synthetic heptapeptide developed in Russia as a structural analogue of tuftsin, a naturally occurring immunomodulatory tetrapeptide. Its sequence, Thr-Lys-Pro-Arg-Pro-Gly-Pro, keeps the tuftsin core at the N-terminus and appends a Pro-Gly-Pro tail. Researchers at the Institute of Molecular Genetics in Moscow synthesized the compound during the 1990s while searching for peptides with combined anxiolytic and immunomodulatory activity. The added tail was intended to resist enzymatic cleavage and prolong the molecule's presence in circulation.
The compound has a calculated molecular weight near 751.9 daltons and carries a net positive charge at physiological pH because of its arginine residue. It dissolves freely in water and in common aqueous buffers, and typically appears as a white or off-white lyophilized powder. The amide backbone makes the molecule susceptible to peptidases, which limits oral use and favors intranasal or parenteral routes. Nomenclature in the literature varies: the substance is also described by the sequence abbreviation TP-7 and by a Russian trade designation.
Once dissolved, the peptide is markedly less stable than the dry powder. Aqueous solutions are subject to backbone hydrolysis and to microbial growth when they are handled without sterile technique. Buffered solutions near neutral pH are common for short-term laboratory work, while acidic conditions are sometimes used to improve solubility. Analytical laboratories generally prepare working solutions fresh rather than storing them, and a residual water film left in a reopened vial can seed degradation even when the container appears dry.
Reversed-phase high-performance liquid chromatography is the standard technique for estimating peptide purity. The result is a peak-area percentage, which describes how much of the detected material elutes as the main peak in one run. Mass spectrometry confirms the molecular mass and can reveal truncated, adducted, or otherwise modified species. Amino acid analysis or tandem mass spectrometry can address sequence fidelity when identity is in doubt. None of these measurements, taken alone, establishes that a sample is fit for any specific purpose.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Analog of the tetrapeptide tuftsin |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Reported consistently across pharmacopoeial descriptions |
| Appearance | White to off-white lyophilized powder | Typical form of research-grade material |
| Solubility | Freely soluble in water | Aqueous buffers; poor in nonpolar solvents |
| Typical storage temperature | -20 degrees Celsius | Lyophilized powder; protect from moisture |
Enzymatic stability motivates the extra three residues at the carboxyl end. Native tuftsin is cleaved quickly by circulating aminopeptidases and carboxypeptidases, which limits its duration of action and its usefulness as a tool compound. Extending the chain with proline-rich segments is a common design tactic because proline constrains the backbone and slows proteolysis. The same Pro-Gly-Pro motif appears in other Russian-developed peptides of the era. Whether the full seven-residue chain is required for activity, or whether it acts mainly as a prodrug releasing tuftsin, remains unresolved.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. Its four N-terminal residues reproduce tuftsin, a tetrapeptide fragment of the immunoglobulin heavy chain, while the C-terminal Pro-Gly-Pro extension is a synthetic addition. The peptide has a molecular mass near 752 daltons and carries a net positive charge at physiological pH because of the arginine and lysine side chains. Published indexes list it under the name Selank and the sequence abbreviation TKPRPGP. Solid-phase peptide synthesis is the standard production route for research quantities.
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.
The next incarnation of King Crimson was radically different from the previous configurations. Fripp's four new recruits were free-improvising percussionist Jamie Muir; drummer Bill Bruford, who had left Yes at a critical and commercial peak in their career in favour of the "darker" Crimson; bassist and vocalist John Wetton, who left Family; and violinist, keyboardist and flautist David Cross, whom Fripp had met when he was invited to a rehearsal of Waves, a band Cross was working in. Fripp and Wetton were this incarnation's primary composers, each writing segments independently and fitting together those which they found compatible. With Sinfield gone, the band asked Wetton's friend Richard Palmer-James, formerly of Supertramp, to be their new lyricist. Unlike Sinfield, Palmer-James was not an official member of King Crimson, having no involvement with the band other than writing lyrics, which he would mail to them from his home in Germany. Following a period of rehearsals, King Crimson resumed touring on 13 October 1972 at the Zoom Club in Frankfurt, with the band's penchant for improvisation and Muir's startling stage presence gaining them renewed press attention.
1993/3253) Customs Duties (ECSC) (Quota and other Reliefs) Order 1993 (S.I. 1993/3254) Medicines (Products Other Than Veterinary Drugs) (Prescription Only) Amendment (No. 2) Order 1993 (S.I. 1993/3256) Tribunals and Inquiries (Friendly Societies) Order 1993 (S.I. 1993/3258) Cardiff—Glan Conwy Trunk Road (A470) (Pentrebach—Cefn Coed Diversion) Order 1993 (S.I. 1993/3259) London Borough of Hackney (Lea Bridge-Cycle/Footbridge) Scheme 1993 Confirmation Instrument 1993 (S.I. 1993/3260) M42 Motorway (Junction 6 Southbound Off-Slip Road to Eastway) Scheme 1993 (S.I. 1993/3261) Export of Goods (Control) (Amendment No. 6) Order 1993 (S.I. 1993/3264) County Court (Amendment No. 4) Rules 1993 (S.I. 1993/3273) Land Registration Rules 1993 (S.I. 1993/3275) Land Registration (Official Searches) Rules 1993 (S.I. 1993/3276)
=== Toxicity due to capping ligands === Some of the capping ligands associated with AuNPs can be toxic while others are nontoxic. In gold nanorods (AuNRs), it has been shown that a strong cytotoxicity was associated with CTAB-stabilized AuNRs at low concentration, but it is thought that free CTAB was the culprit in toxicity . Modifications that overcoat these AuNRs reduces this toxicity in human colon cancer cells (HT-29) by preventing CTAB molecules from desorbing from the AuNRs back into the solution. Ligand toxicity can also be seen in AuNPs. Compared to the 90% toxicity of HAuCl4 at the same concentration, AuNPs with carboxylate termini were shown to be non-toxic. Large AuNPs conjugated with biotin, cysteine, citrate, and glucose were not toxic in human leukemia cells (K562) for concentrations up to 0.25 M. Also, citrate-capped gold nanospheres (AuNSs) have been proven to be compatible with human blood and did not cause platelet aggregation or an immune response. However, citrate-capped gold nanoparticles sizes 8-37 nm were found to be lethally toxic for mice, causing shorter lifespans, severe sickness, loss of appetite and weight, hair discoloration, and damage to the liver, spleen, and lungs; gold nanoparticles accumulated in the spleen and liver after traveling a section of the immune system. There are mixed-views for polyethylene glycol (PEG)-modified AuNPs. These AuNPs were found to be toxic in mouse liver by injection, causing cell death and minor inflammation.
=== 1945–1946 === After the end of the war, Amin al-Husayni managed to find his way to Egypt and stayed there until 1959, when he moved to Lebanon. On 22 March 1945, the Arab League was formed. In November 1945, on the urging of Egypt, its leading member, the then seven members of the Arab League (Lebanon, Syria, Iraq, Jordan, Saudi Arabia, Egypt, and Yemen) reconstituted the Arab Higher Committee comprising twelve members as the supreme executive body of Palestinian Arabs in the territory of the British Mandate of Palestine. The committee was dominated by the Palestine Arab Party, controlled by the Husayni family, and was immediately recognised by Arab League countries. The Mandate government recognised the new committee two months later. In February 1946, Jamal al-Husayni returned from exile to Palestine and immediately set about reorganising and enlarging the committee, becoming its acting president. The members of the reconstituted committee as at April 1946 were:
Sources: en.wikipedia.org
After 1957, the new South African Defence Force was faced with a post-war upsurge in African nationalism, and forced to expand its resources accordingly. In 1963 its total strength stood at around 25,000 men. By 1977, the United Nations was imposing arms sanctions on the republic due to its controversial policy of racial apartheid. South Africa responded by developing a powerful domestic arms industry, capable of producing quality hardware, including jet fighters, drones, guided missiles, armoured cars, multiple rocket launchers, and small arms. SADF units fought in the Angolan Civil War during Operation Savannah and were also active alongside Rhodesian Security Forces during the Rhodesian Bush War. Although both campaigns were strategically unsuccessful, it was clearly proven that South Africa's military was immeasurably superior in strength and sophistication than all her African neighbours combined. Further enlargement and modernisation of the armed forces continued under former defence minister Pieter Willem Botha, who became state president in 1984. Shortly after Botha took office, the SADF numbered some 83,400 men (including 53,100 conscripts and 5,400 non-whites): one armoured brigade, one mechanised infantry brigade, four motorised brigades, one parachute brigade, a special reconnaissance regiment, one Marine brigade, twenty artillery regiments, supporting specialist units, a balanced air force, and a navy adequate for coastal protection in all.
== Structure == Bacterial glutathione transferases of all classes are homodimeric enzymes (although heterodimeric isozymes of certain classes are also known). Monomers fold into a two-domain configuration to form the active enzyme structure. These globular proteins have an N-terminal domain that consists of a mixture of alpha-helices and beta strands, while the C-terminal domain is all-helical. The N-terminal domain contains the glutathione-binding site and is a highly conserved region among all GSTs. This domain has a similar composition to thioredoxins, which act as antioxidants by facilitating the reduction of other proteins. In comparison, the region that contains the greatest amount of variability between GST classes is contained in the alpha-2 helix on the C-terminal domain. The predominantly alpha-helical C-terminal domain is involved with the binding of hydrophobic substrates (such as hydrophobic portions of xenobiotics). The specificity of the alpha-2 helix stems from the assortment of amino acids in the domain that interacts with the glycine residue of glutathione.
Coiled-coil drug delivery systems refer to drug delivery systems utilizing coiled-coil motifs capable of delivering disease-treating therapies, imaging agents, and vaccines to patients systemically or specifically. These systems are a form of peptide therapeutics and are capable of being engineered and finely tuned into different types of drug delivery vehicles (such as liposomes, nanoparticle drug carriers, polymer hybrid drug carriers, micelles, etc.) based on the specific application required. The goal of a coiled-coil drug delivery system is to deliver cargo such as medication, imaging agents, biological molecules, or vaccines efficiently and specifically, in order to maximize the therapeutic efficacy and minimize unwanted side effects. This is achieved through fine-tuning the factors affecting the coiled coil's oligomerization, resulting in modular systems that are highly specific for the intended application. Coiled-coil motifs make up 10% of all protein sequences, and are utilized naturally by various proteins in both prokaryotes and eukaryotes to achieve diverse cellular functions. Coupled with the simple helical structure of coiled coils which has been widely studied and reported on in literature, engineered coiled coil drug delivery systems are capable of improving drug pharmacokinetics, reducing unintentional toxicity during delivery, delivering drugs in a specific manner, controlling cargo release, and maintaining high stability through transport in the body.
==== Alkylation of enolates ==== Alkylation of the bis-paramethoxybenzyl (pMB) protected 2,5-DKP 1 using the base LHMDS and an alkyl bromide R1Br, gave the mono-alkylated derivative 2, which on further alkylation gave the symmetrical trans-disubstituted derivative 3
Suvomipic (INNTooltip International Nonproprietary Name; developmental code names PP405 and JXL069) is a drug acting as a mitochondrial pyruvate carrier (MPC) inhibitor which is under development for the treatment of alopecia (hair loss), specifically androgenic alopecia (pattern hair loss). It is used topically as a 0.05% concentration gel on the scalp once-daily. Suvomipic is a possible first-in-class drug with a novel mechanism of action in the potential treatment of hair loss. The drug's generic name and chemical structure were published in July 2026, revealing PP405 to be the existing compound JXL069.
Sources: en.wikipedia.org
== Signs and symptoms == These descriptions refer to 'classic' Alport syndrome, which usually causes significant disease from young adult or late childhood life. Some individuals, usually with milder mutations or 'carrier' status, develop disease later, or show only some of the features of classic disease.
Tianeptine/naloxone (developmental code names TNX-601, TNX-601-CR, TNX-601-ER), or naloxone/tianeptine, is an extended-release combination of tianeptine, an atypical μ-opioid receptor agonist, and naloxone, an orally inactive μ-opioid receptor antagonist, which was under development for the treatment of major depressive disorder, post-traumatic stress disorder (PTSD), and neurocognitive dysfunction associated with corticosteroid use but was never marketed. Whereas tianeptine is marketed widely throughout Europe, Asia, and Latin America but is not available in the United States or the United Kingdom, tianeptine/naloxone was under development for registration in the United States and other countries. In addition, whereas tianeptine has a short duration of action and requires administration three times per day, tianeptine/naloxone was developed as an extended-release formulation with enhanced pharmacokinetics suitable for once-daily administration. The combination formulation employs tianeptine as the oxalate salt, which is said to have improved physicochemical properties for use in the extended-release formulation compared to the amorphous tianeptine sodium that is used in immediate-release tianeptine-only formulations. Naloxone is used in misuse-resistant oral drug formulations as it is inactive if taken orally but becomes active if oral tablets are crushed and administered parenterally, such as by injection.
=== Restenosis === Paclitaxel is used as an antiproliferative agent for the prevention of restenosis (recurrent narrowing) of coronary and peripheral stents; locally delivered to the wall of the artery, a paclitaxel coating limits the growth of neointima (scar tissue) within stents. Paclitaxel drug-eluting stents for coronary artery placement are sold under the trade name Taxus by Boston Scientific in the United States. Paclitaxel drug-eluting stents for femoropopliteal artery placement are also available.
Keratoglobus is a very rare condition that causes corneal thinning primarily at the margins, resulting in a spherical, slightly enlarged eye. It may be genetically related to keratoconus. Pellucid marginal degeneration causes thinning of a narrow (1–2 mm) band of the cornea, usually along the inferior corneal margin. It causes irregular astigmatism that, in the early stages of the disease can be corrected by spectacles. Differential diagnosis may be made by slit-lamp examination. Posterior keratoconus, a distinct disorder despite its similar name, is a rare abnormality, usually congenital, which causes a nonprogressive thinning of the inner surface of the cornea, while the curvature of the anterior surface remains normal. Usually only a single eye is affected. Post-LASIK ectasia is a complication of LASIK eye surgery.
Kardashev mentions another hypothesis that, in his opinion, is capable of explaining the dynamics of the supercivilizations: the "feedback effect" (theorized by Sebastian von Hoerner in 1975), which is based on the hypothesis that at a high technological level, civilizations tend to converge rather than to isolate themselves. The distance between supercivilizations could then be determined by half the time of the technological evolution of the oldest civilization, which would be about 3 to 4 billion years. On the other hand, this supercivilization may not have been present in our galaxy for a long time. Kardashev concludes by saying that since the expansion of the Universe is infinite, the number and lifetime of such supercivilizations are also infinite.
Sources: en.wikipedia.org
Selank is a synthetic seven-amino-acid peptide modeled on tuftsin, a fragment of the immunoglobulin G heavy chain. It was designed in Russia to combine anxiolytic and immunomodulatory properties in one molecule.
The first four residues of Selank reproduce the tuftsin sequence Thr-Lys-Pro-Arg. A Pro-Gly-Pro extension at the C-terminus was added to slow enzymatic breakdown and extend residence time.
It holds marketing authorization in Russia, where nasal drop formulations are sold. No equivalent approval exists in the European Union, the United States, or most other countries.
Sealed, desiccated storage at -20 °C or colder is the standard recommendation for research-grade material. Vials should reach room temperature before they are opened, which limits condensation. Repeated temperature cycling is discouraged.