Testagen peptide is a lyophilized vial of the tetrapeptide Lys-Glu-Asp-Gly, written KEDG, the testes-directed compound in the Khavinson bioregulator range. Its calculated mass sits roughly one dalton from Bronchogen, which is an analytical hazard worth knowing about.
Specification Table
Testagen chemical and handling data
| Property |
Value |
| Compound |
Testagen |
| Sequence designation |
KEDG |
| Amino acid sequence |
Lysine-Glutamate-Aspartate-Glycine |
| Sequence provenance |
Secondary sources, converging. Not traced to a single primary citation. Confirm against the lot certificate before relying on it for calculation |
| Residue count |
4 |
| Molecular weight, calculated |
447.5 g/mol, computed from standard residue masses plus water rather than quoted from a paper |
| Near-isobaric relative |
Bronchogen at approximately 446.5, roughly one dalton lighter |
| Oxidation-prone residues |
None |
| Chromophore |
None. Concentration cannot be determined by 280 nm absorbance |
| Structural note |
Glycine at the carboxy terminus gives maximum backbone flexibility, the opposite of a proline terminus |
| Compound class |
Short peptide bioregulator, cytogen subclass |
| Source tissue of the parent fraction |
Testicular tissue |
| Originating programme |
St Petersburg Institute of Bioregulation and Gerontology |
| Programme lead |
Vladimir Khavinson |
| Proposed mechanism in the literature |
Sequence-specific interaction with DNA, modulating tissue-associated gene expression |
| Mechanism status |
Hypothesis. Not independently established outside the originating programme |
| Receptor |
None identified |
| Appearance |
White lyophilized powder |
| Purity |
Per lot-specific certificate of analysis |
| Solubility |
Water soluble |
| Storage, lyophilized |
2-8°C or -20°C, protected from light and moisture |
| Regulatory status |
No approved human or veterinary formulation in any jurisdiction |
Why Does Testagen Sit One Dalton From Bronchogen?
The Testagen peptide mass coincidence is the most practically useful thing on this page and no competitor selling both compounds mentions it.
Testagen is Lys-Glu-Asp-Gly, calculated at roughly 447.5, and bronchogen is Ala-Glu-Asp-Leu, calculated at roughly 446.5. The two differ by about one dalton.
That is within the resolution of a bench-grade mass spectrometer operating at unit resolution. A laboratory confirming identity on such an instrument cannot reliably distinguish the two compounds by mass alone.
The sequences are entirely different, and testagen opens with lysine and ends in glycine. Bronchogen opens with alanine and ends in leucine. Only the arithmetic of their residue masses brings the totals so close together.
High-resolution mass spectrometry resolves them, because the exact masses differ in their decimal places even when the nominal masses do not. So does amino acid analysis, which reports composition directly and would show lysine present in one and absent from the other.
Chromatography separates them easily as well, since a leucine-containing peptide is considerably more hydrophobic than a glycine-terminating one. The hazard is specifically in relying on nominal mass as a sole identity check.
What Is a Testes Bioregulator?
The organ term draws far more search volume than Testagen peptide does, and it describes the programme premise rather than a pharmacological category.
Khavinson and colleagues fractionated organ extracts on the idea that each contains short peptides carrying tissue-specific regulatory information, then named each resulting compound for its source organ.
Testagen came from testicular tissue in that work. The name records the source, not a demonstrated site of action.
That distinction matters because the organ naming implies a tissue destination that no published tissue-distribution study across this family supports. The implication is inherited from methodology rather than measured.
The class splits into cytomaxes, which are tissue extracts, and cytogens, which are defined synthetic sequences. Testagen is a cytogen and can therefore be characterised completely by routine analysis, unlike an extract.
Until distribution work exists, organ names in this family are best read as programme labels describing where a compound came from rather than statements about where it goes.
What Does a Glycine Terminus Change?
Testagen peptide ends in glycine, and among the tetrapeptides in this family that is the least constrained possible ending.
Glycine has a single hydrogen as its side chain. It is the smallest residue and it permits backbone angles that no other amino acid can adopt, which makes any glycine-containing region unusually flexible.
At a chain terminus that flexibility is the opposite of what Prostamax and Cortagen achieve with proline. Where a terminal proline obstructs carboxypeptidases, a terminal glycine presents them with an easy substrate.
The practical implication is that Testagen should be more susceptible to carboxy-terminal degradation than its proline-terminating relatives in any system with peptidase activity.
Nobody appears to have published a comparative stability study across the family, which is another cheap and obvious experiment the sequence set makes available.
Epitalon shares the glycine terminus on an alanine-opening backbone, making it the natural comparator if that question is ever addressed directly.
What Testagen Peptide Dosage Figures Are Published?
The figures below come from published studies in the species those studies used, and the family caveats travel with them.
Published rodent studies occupy the microgram per kilogram band by parenteral routes. That matches the rest of the Khavinson range and sits far below most of this catalogue.
The Russian clinical record describes discrete courses of ten to twenty days at amounts in the tens to low hundreds of micrograms rather than continuous exposure.
That schedule is reported alongside the quantity in the primary descriptions and dropped from most secondary summaries, which is how a course-based figure becomes misread as a daily one.
No receptor affinity is known, so no concentration can be justified from first principles and wide ranging is a requirement.
Cross-species conversion requires allometric scaling through body surface area rather than arithmetic on body weight.
What Should Testagen For Sale Documentation Show?
For Testagen peptide the near-isobaric relationship with Bronchogen makes one certificate field considerably more important here than elsewhere.
Measured mass at high resolution, not unit resolution. A figure reported as 447 tells you very little when a sibling compound sits at 446.5 and the instrument cannot separate them.
Amino acid analysis as the confirming check. It reports composition directly and would show lysine present in Testagen and absent from Bronchogen, which resolves the ambiguity that mass alone cannot.
Sequence stated explicitly as Lys-Glu-Asp-Gly rather than by trade name, since four compounds in this family share Lys-Glu-Asp and differ only at the terminus.
Counterion identity, with the net peptide content figure beside it. At 447.5 daltons a single trifluoroacetate at 114 is roughly 20 percent of the associated mass.
Purity by reversed-phase chromatography, noting that a glycine-terminating polar tetrapeptide retains poorly on standard gradients and the method needs adapting.
What Does Testagen Peptide Share With the Rest of the Range?
The family reads as a designed series once the sequences sit side by side.
Testagen peptide is Lys-Glu-Asp-Gly. Vesugen is the same minus the glycine. Livagen substitutes alanine at that terminal position, Pancragen tryptophan, Prostamax proline.
A second series opens with alanine rather than lysine, and Epitalon within it is Ala-Glu-Asp-Gly, which is Testagen peptide with its first residue swapped.
That pairing is the most interesting comparison available in the whole family. Two compounds identical at three of four positions, assigned to entirely different organs, differing only in whether position one is lysine or alanine.
If the tissue-specificity claim holds, those two should behave differently in a matched assay. If it does not, they should behave alike.
Nobody appears to have run that comparison, and it would take one plate.
How Should the Vial Be Stored?
Testagen peptide is chemically undemanding, so the handling notes are correspondingly short.
No cysteine, no methionine, no tryptophan and no asparagine-glycine motif in a degradation-relevant position. The routes that trouble most peptides are unavailable.
Store dry powder sealed against light and moisture, at 2 to 8 degrees Celsius or below. Nothing more elaborate is needed.
Water solubility is good, helped by the small terminal residue, so introduce diluent gently along the vial wall and swirl instead of shaking.
Reconstituted solution at 2 to 8 degrees, aliquoted before freezing. Freeze-thaw tolerance is good.
Record lot, measured mass with the instrument resolution stated, counterion, net peptide content, diluent, volume, concentration and date.
A last note on ordering across near-isobaric compounds. Where a laboratory stocks several bioregulators, labelling vials by sequence rather than trade name removes an entire category of mix-up.
Writing KEDG on the Testagen tube and AEDL on the Bronchogen tube costs nothing and makes the difference visible at the bench rather than only on a certificate filed elsewhere.
It also makes the family structure legible to anyone picking up the work later, which is worth more than it sounds.
A closing note on the glycine and the family arithmetic. Glycine is the smallest residue at 57 daltons, which is why substituting it at the terminus pulls Testagen peptide close to Bronchogen despite the leucine at 113 sitting there instead.
Lysine at 128 against alanine at 71 opens a 57 dalton gap at the front, and leucine against glycine closes a 56 dalton gap at the back. The two nearly cancel.
That is the whole explanation for the coincidence, and it is worth understanding rather than memorising, because the same arithmetic can bring other pairs close together as the family grows.
Nothing about it is mysterious. It is addition.
Anyone stocking more than three or four of these compounds should expect to meet the problem again eventually, and labelling by sequence is the cheapest possible insurance against it.
One further note on the two series and where Testagen peptide sits between them. Its lysine opening places it with Vesugen, Livagen, Pancragen and Prostamax, while its glycine terminus places it alongside Epitalon from the alanine series.
That makes it the natural bridge compound for anyone wanting to test whether the opening residue or the terminal residue carries more of the assigned tissue behaviour.
Two compounds, one plate, one afternoon.
Whoever runs it will have tested the programme central claim more directly than five decades of single-compound publication managed to.
Published Literature
References verified against the publisher record. As across this family, the literature originates almost entirely from one research programme.
- Khavinson VK, Malinin VV. Gerontological Aspects of Genome Peptide Regulation. Karger, Basel; 2005.
- Khavinson VK. Neuroendocrinology Letters. 2002;23(Suppl 3):11-144.
- Anisimov VN, Khavinson VK. Critical Reviews in Oncology/Hematology. 2010;74(1):46-66.
- Fedoreyeva LI, Kireev II, Khavinson VK, Vanyushin BF. Biochemistry (Moscow). 2011;76(11):1210-1219.
- Khavinson VK, Solovyov AY, Zhilinsky DV, Shataeva LK, Bandaletova TY. Bulletin of Experimental Biology and Medicine. 2012;153(4):500-505.
Frequently Asked Questions
What is Testagen peptide?
A lyophilized vial of the tetrapeptide Lys-Glu-Asp-Gly, written KEDG, the testes-directed compound in the Khavinson bioregulator range. For laboratory research purposes only, and not approved for any use in any jurisdiction.
Why does it sit one dalton from Bronchogen?
Coincidence of residue arithmetic. Testagen calculates to roughly 447.5 and Bronchogen to roughly 446.5, despite entirely different sequences, and testagen opens with lysine and ends in glycine; Bronchogen opens with alanine and ends in leucine.
Why does that matter practically?
Because one dalton is within the resolution of a bench-grade instrument operating at unit resolution, and a laboratory confirming identity that way cannot reliably distinguish the two compounds by mass alone.
How can they be told apart?
High-resolution mass spectrometry, because the exact masses differ in their decimal places, and amino acid analysis also resolves it, reporting lysine present in Testagen and absent from Bronchogen.
Does chromatography separate them?
Easily. A leucine-containing peptide is considerably more hydrophobic than a glycine-terminating one, so they elute well apart. The hazard is specifically in relying on nominal mass as a sole identity check.
What is a testes bioregulator?
It describes the programme premise rather than any pharmacological category. Testagen came out of testicular tissue during fractionation, so the name records a source rather than a demonstrated site of action.
What does the glycine terminus change?
It makes the chain end maximally flexible. Glycine has a single hydrogen as its side chain and permits backbone angles no other residue can adopt, which is the opposite of what a terminal proline achieves.
What follows for stability?
Testagen should be more susceptible to carboxy-terminal degradation than its proline-terminating relatives in any system with peptidase activity, since a terminal glycine presents carboxypeptidases with an easy substrate.
Has that been tested?
Not that I could find. No comparative stability study across the family appears in the published record, which is another cheap experiment the sequence set makes available and nobody has run.
What dosage figures are published?
Published rodent studies sit in the microgram per kilogram band by parenteral routes, with the Russian clinical record describing discrete ten to twenty day courses at tens to low hundreds of micrograms.
What should the certificate emphasise?
Measured mass at high resolution rather than unit resolution, plus amino acid analysis as the confirming check. A figure reported as 447 tells you little when a sibling compound sits at 446.5.
Compliance Statement
Testagen peptide is sold exclusively for laboratory research use. It is not a drug, food, or cosmetic product, and it is not a dietary product of any kind. It is not approved by the FDA or any comparable authority for human or veterinary use, its proposed mechanism has not been independently established, and amounts cited are figures from published studies in the species those studies used. This product is not intended to diagnose, treat, cure, or prevent any disease. It must not be given to humans or animals. Purchase is restricted to qualified researchers and institutions operating within applicable laws. All handling is the responsibility of the purchasing laboratory.
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