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Peptide Identity And Structure — Background and Details

By Editorial Desk · published 2026-04-23 · last reviewed 2026-05-19 · Guide

Tuftsin 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.

Updated 2026-05-19. Numbers and descriptions here follow the published literature rather than marketing material.

Peptide Identity and Structure

Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter notation. Its structure consists of the immunomodulatory tetrapeptide tuftsin, Thr-Lys-Pro-Arg, extended at the carboxyl terminus by a Pro-Gly-Pro segment. The molecular formula is commonly given as C33H57N11O9, corresponding to a monoisotopic mass near 751.4 Da and an average molecular mass near 751.9 Da. All seven residues are proteinogenic amino acids, and the molecule carries no modified side chains or non-natural linkages.

The compound was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences during the 1980s and 1990s. The stated design goal was to retain the immunomodulatory and central nervous system activity attributed to tuftsin while improving resistance to enzymatic breakdown. Adding a proline-rich tail to the short parent peptide was a deliberate strategy, because proline residues restrict the conformations available to many peptidases. The same laboratory produced Semax, an ACTH fragment analog, and both compounds were developed in parallel as short, enzymatically stabilized peptides intended for intranasal use.

Origins and Proposed Mechanisms

Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.

Published clinical evidence is limited. Most controlled trials were conducted in Russia, enrolled modest numbers of participants, and appeared in Russian-language journals, which restricts independent verification. Reported outcomes include lower anxiety scores, improved attention and memory measures, and changes in fatigue ratings. Reviews written in English note methodological limitations such as small samples and inconsistent endpoints. Whether the compound produces clinically meaningful benefit relative to established anxiolytics is therefore an open question rather than an established finding.

Selank at a glance

PropertyValueNotes
Peptide sequenceThr-Lys-Pro-Arg-Pro-Gly-ProSeven residues; tuftsin plus a Pro-Gly-Pro tail
Molecular formulaC33H57N11O9Commonly reported value for the free peptide
Monoisotopic massRoughly 751.4 DaAverage molecular mass near 751.9 Da
AppearanceWhite to off-white powderTypically supplied as a lyophilized solid
Solubility classFreely soluble in waterAlso dissolves in saline and other polar solvents

Selank Origin and Chemical Identity

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.

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Background and Peptide Identity

Reported activity for Selank centers on anxiolytic and nootropic effects. Russian clinical reports describe use in anxiety and in cognitive or attention-related complaints. Most of this evidence comes from studies conducted by the same research groups that developed the peptide. Independent replication in other countries remains limited, and no major Western regulatory agency has approved the compound for any indication. The gap between local reports and external verification is a recurring point in discussions of the peptide.

Tuftsin, the parent structure, is a naturally occurring immunomodulatory tetrapeptide released from the Fc region of immunoglobulin G by spleen enzymes. Selank extends this four-residue sequence with three additional amino acids. The stated rationale is that the added tail slows enzymatic breakdown and may influence receptor interactions. How the full heptapeptide behaves at the molecular level is not firmly established, and proposed mechanisms often involve indirect modulation of neurotransmitter or immune signaling rather than a single defined target.

Reference notes

=== Supporters === Pritzker has gained support from progressives and socialists for his stances on healthcare, education, raising the minimum wage, legalizing recreational marijuana, and expanding access to healthcare. His administration has been considered one of the most progressive in the United States.

=== Operation Freedom's Sentinel === The 1st BCT deployed to Afghanistan in support of Operation Freedom's Sentinel from June 2017 to March 2018. Two soldiers were killed in action when their convoy was purposefully hit by a vehicle filled with explosives. The 3rd BCT deployed to Afghanistan in support of Operation Freedom's Sentinel from July 2019 to March 2020. In February 2020 soldiers from the 1st BCT, 10th Mountain Division were deployed to Afghanistan to replace the 3rd BCT as part of a unit rotation.

The Government of India refused the offer from Union Carbide, and claimed US$3.3 billion. The Indian Supreme Court told both sides to come to an agreement and "start with a clean slate" in November 1988. Eventually, in an out-of-court settlement reached in February 1989, Union Carbide agreed to pay US$470 million for damages caused in the Bhopal disaster. The amount was immediately paid. Throughout 1990, the Indian Supreme Court heard appeals against the settlement. In October 1991, the Court upheld the original $470 million, dismissing any other outstanding petitions that challenged the original decision. It ordered the Indian government "to purchase, out of settlement fund, a group medical insurance policy to cover 100,000 persons who may later develop symptoms" and cover any shortfall in the settlement fund. It also requested UCC and its subsidiary UCIL "voluntarily" fund a hospital in Bhopal, at an estimated $17 million, to specifically treat victims of the Bhopal disaster. The company agreed to this.

=== Discovery of catalytic RNA (ribozymes) === An experimental system was developed in which an intron-containing rRNA precursor from the nucleus of the ciliated protozoan Tetrahymena could be spliced in vitro. Subsequent biochemical analysis shows that this group I intron was self-splicing; that is, the precursor RNA is capable of carrying out the complete splicing reaction in the absence of proteins. In separate work, the RNA component of the bacterial enzyme ribonuclease P (a ribonucleoprotein complex) was shown to catalyze its tRNA-processing reaction in the absence of proteins. These experiments represented landmarks in RNA biology, since they revealed that RNA could play an active role in cellular processes, by catalyzing specific biochemical reactions. Before these discoveries, it was believed that biological catalysis was solely the realm of protein enzymes.

Sources: en.wikipedia.org

Notes from published material

== Finance minister == FinanceAsia for the second year running has ranked the finance ministers of the Asia-Pacific region's 12 largest economies. In the 2016 ranking, Thailand's Apisak Tantivorawong was ranked 11th (1=best, 12=worst). Ranked worst was Malaysia's Najib Razak.

One area in which population categories can be important considerations in genetics research is in controlling for confounding between population substructure, environmental exposures, and health outcomes. Association studies can produce spurious results if cases and controls have differing allele frequencies for genes that are not related to the disease being studied, although the magnitude of this problem in genetic association studies is subject to debate. Various methods have been developed to detect and account for population substructure, but these methods can be difficult to apply in practice. Population substructure also can be used to advantage in genetic association studies. For example, populations that represent recent mixtures of geographically separated ancestral groups can exhibit longer-range linkage disequilibrium between susceptibility alleles and genetic markers than is the case for other populations. Genetic studies can use this admixture linkage disequilibrium to search for disease alleles with fewer markers than would be needed otherwise. Association studies also can take advantage of the contrasting experiences of racial or ethnic groups, including migrant groups, to search for interactions between particular alleles and environmental factors that might influence health.

=== Split-&-Pool DNA Encoding === In order to apply combinatorial chemistry for the synthesis of DNA-encoded chemical libraries, a Split-&-Pool approach was pursued. Initially a set of unique DNA-oligonucleotides (n) each containing a specific coding sequence is chemically conjugated to a corresponding set of small organic molecules. Consequently, the oligonucleotide-conjugate compounds are mixed ("Pool") and divided ("Split") into a number of groups (m). In appropriate conditions a second set of building blocks (m) are coupled to the first one and a further oligonucleotide which is coding for the second modification is enzymatically introduced before mixing again. This “split-&-pool” steps can be iterated a number of times (r) increasing at each round the library size in a combinatorial manner (i.e. (n x m)r). Alternatively, peptide nucleic acids have been used to encode libraries prepared by "split-&-pool" method. A benefit of PNA-encoding is that the chemistry can be performed by standard SPPS.

=== Selective serotonin reuptake inhibitors === Selective serotonin reuptake inhibitors (SSRIs) selectively inhibit the reuptake of serotonin and are a widely used group of antidepressants. With increased receptor selectivity compared to TCAs, undesired effects such as poor tolerability are avoided. Serotonin is synthesized from an amino acid called L-tryptophan. Active transport system regulates the uptake of tryptophan across the blood–brain barrier. Serotonergic pathways are classified into two main ways in the brain: the ascending projections from the medial and dorsal raphe and the descending projections from the caudal raphe into the spinal cord.

=== Early clinical trials, supply and the transfer to BMS === Phase I clinical trials began in April 1984, and the decision to start Phase II trials was made a year later. These larger trials needed more bark and collection of a further 12,000 pounds was commissioned, which enabled some phase II trials to begin by the end of 1986. But by then it was recognized that the demand for taxol might be substantial and that more than 60,000 pounds of bark might be needed as a minimum. This unprecedentedly large amount brought ecological concerns about the impact on yew populations into focus for the first time, as local politicians and foresters expressed unease at the program. The first public report from a phase II trial in May 1988 showed promising effects in melanoma and refractory ovarian cancer. At this point, Gordon Cragg of the NCI's Natural Product Branch calculated the isolation of enough taxol to treat all the ovarian cancer and melanoma cases in the US would require the destruction of 360,000 trees annually. For the first time, serious consideration was given to the problem of supply.

Sources: en.wikipedia.org

Further detail

==== Automation and workplace surveillance ==== The TUC has warned against the "uncritical use" of AI and algorithmic management in the workplace. In 2022, the TUC published a report stated that intrusive worker surveillance technology was "spiralling out of control", noting that 60% of workers believed they had been subject to surveillance at their current or most recent job. The TUC highlighted that AI-powered technologies were increasingly being used to analyse facial expressions, tone of voice, and accents during recruitment, and to make automated decisions regarding shift allocation and redundancies. In August 2025, the TUC launched its "worker first" AI strategy, titled Building a Pro-Worker AI Innovation Strategy. The strategy called for a "digital dividend" to ensure workers share in the productivity gains generated by AI. The TUC's demands included:

Systems or family therapy works with couples and families, and emphasizes family relationships as an important factor in psychological health. The central focus tends to be on interpersonal dynamics, especially in terms of how change in one person will affect the entire system. Therapy is therefore conducted with as many significant members of the "system" as possible. Goals can include improving communication, establishing healthy roles, creating alternative narratives, and addressing problematic behaviors.

== Human Proteome Organization == The major awards of the Human Proteome Organization are the Distinguished Achievement in Proteomic Sciences Award, Discovery in Proteomic Sciences Award, Clinical & Translational Proteomics Award, Science & Technology Award, and Distinguished Service Award.

Frank Walter Blake Vale (26 October 1908 – 21 May 2006) was an Australian businessperson who was a leading pioneer of the Australian cold chain industry's mechanical refrigeration era and of the modern Victorian dairy industry. He was a manager and leader who both applied and contributed to the engineering and marketing of the various steps in the cold chain.

Sources: en.wikipedia.org

Frequently asked questions

What is the primary sequence of Selank?

The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter code. It combines the tetrapeptide tuftsin with a carboxyl-terminal Pro-Gly-Pro extension. This full sequence identifies the molecule more precisely than the research name.

Is Selank found naturally in the body?

No peptide with this exact sequence has been identified as an endogenous substance. It is a laboratory-designed analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The Pro-Gly-Pro extension has no known natural source.

Why does the peptide contain three proline residues?

Proline introduces conformational constraints that make a peptide less accessible to common peptidases. This is a standard stabilization strategy in peptide design. The added residues also increase the distance between the active tuftsin portion and typical cleavage sites.

What is Selank made of?

It is a seven-amino-acid peptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro, produced by chemical synthesis rather than extracted from biological tissue. Its design is based on tuftsin, a natural immunomodulatory tetrapeptide. The C-terminal Pro-Gly-Pro segment is a common stabilising motif in short regulatory peptides.

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