Crystagen

1 Identity

Short-chain bioregulator (Khavinson class), sequence not fixed — see status. Sold within the Khavinson synthetic short-peptide ('Cytogen') line alongside Vilon, Vesugen, Pinealon, Cartalax and Chonluten.

Sequence

Not fixed. This is the finding of the record, not a gap in it. Two live listings publish different molecules under this name, and until the sequence is fixed the record cannot carry a mass. The sequence most commonly attributed in the Khavinson class literature and on the majority of vendor pages is H-Glu-Asp-Pro-OH (EDP) — a linear all-L tripeptide, free N-terminal alpha-amino group, free C-terminal carboxyl, no disulfide, no acylation, no amidation, no non-proteinogenic residue, two carboxyl side-chain functions against a single basic center, and no aromatic residue and therefore no 280 nm chromophore. That attribution is recorded as an attribution and is not asserted as this record's identity. Attribution and verification are two different kinds of knowledge and this catalog does not merge them.

Molecular formula

C14H21N3O8 for the free acid IF the article is H-Glu-Asp-Pro-OH. Stated conditionally and deliberately: no formula is asserted for Crystagen until the sequence conflict is closed. The candidate formulas are set out with the candidate masses below, so that a single accurate-mass measurement can decide the question.

Average mass

No mass is asserted. Candidate arithmetic, each figure taken from the residue composition on IUPAC 2021 conventional atomic weights, so the conflict is resolvable by one measurement rather than by argument: H-Glu-Asp-Pro-OH (EDP), C14H21N3O8, 359.334 Da. H-Ala-Glu-Asp-Pro-OH (AEDP, which is Cortagen), C17H26N4O9, 430.414 Da. H-Lys-Glu-Asp-Pro-OH (KEDP, which is Prostamax), C20H33N5O9, 487.510 Da. The three candidates are separated by 71 and 57 Da, far outside any instrument tolerance, so a single ESI-MS run on a vendor sample settles which molecule that vendor is shipping. The cost of clearing this gate is one injection.

Monoisotopic mass

No mass is asserted. Candidate monoisotopic neutrals: EDP 359.13286 Da, working ions [M+H]+ 359.14014 and [M-H]- 359.12558; AEDP 430.16998 Da; KEDP 487.22783 Da. A plus or minus 5 ppm window on the EDP neutral is plus or minus 0.0018 Da, which is two orders of magnitude tighter than the 71 Da separating the candidates — the point being that this is not a difficult measurement, and that the uncertainty here is administrative rather than analytical.

Salt / variant note

The confusable set is the whole point of this record. (1) Cortagen, H-Ala-Glu-Asp-Pro-OH, 430.414 avg — shares the Glu-Asp-Pro motif and differs by a single N-terminal Ala. (2) Prostamax, H-Lys-Glu-Asp-Pro-OH, 487.510 avg — same motif, N-terminal Lys. (3) Cartalax, H-Ala-Glu-Asp-OH, 333.297 avg — the closest low-mass neighbor to the EDP candidate at 26 Da, and itself already flagged in this catalog for a 46 ppm monoisotopic collision with Thymagen (Glu-Trp, 333.344 avg). (4) Pinealon (Glu-Asp-Arg, EDR) and Chonluten (Glu-Asp-Gly, EDG), which share the Glu-Asp dipeptide head. (5) Vladonix, the thymus organ-extract preparation Crystagen is marketed as the synthetic counterpart of — an undefined polypeptide fraction, panel P7, not comparable by any assay. Note that the permutations of any fixed residue set are isobaric, so mass separates the candidates above but cannot separate EDP from DEP or PED; only MS/MS or Edman does that.

2 Class & testing panel

Form

Single article

Testing panel

P1 — panel definitionprovisionally, contingent on the sequence being fixed. If the resolved sequence proves to contain only proteinogenic L-residues in a short linear chain with a free N-terminus and free C-terminus, P1 is correct. The panel cannot be finalized before the identity is, and the provisional assignment stays marked provisional rather than being allowed to harden by repetition

3 Primary sources & evidence

The index reports the design and provenance of the literature, not a conclusion about effect.

No compound-specific literature is cited here, because no compound is yet fixed to cite it against, and a citation list assembled under an ambiguous trade name would attribute the wrong papers to the wrong molecule — which is the precise error this record exists to prevent. What can be stated: the Khavinson short-peptide class as a whole carries in-vitro and rodent literature concentrated in the publication network of the Saint Petersburg Institute of Bioregulation and Gerontology, largely in Russian-language journals and their English translations, with sparse independent replication; the class evidence grades D. No compound-specific ClinicalTrials.gov registration under this trade name was identified. No marketing authorization in any jurisdiction. When the sequence is fixed, the literature is searched against the sequence and the systematic name rather than against the trade name.

4 Storage & specification

Storage

Lyophilized powder at -20 degrees C plus or minus 5 degrees C, desiccated with in-pack desiccant, protected from light; 2 to 8 degrees C is acceptable for transit and for working stock held no longer than 30 days. Sealed vials are equilibrated to room temperature before opening. The condition is confirmed against the resolved sequence rather than assumed from the trade name, because a storage condition validated against the wrong molecule is not a storage condition.

Shelf life

Every lot is dated from the date of QA release and carries a printed retest date, and first-expiry-first-out is enforced against that printed date. The protocol assignment for a short all-L peptide with no disulfide, no methionine, no tryptophan and no aspartyl-glycine motif is a provisional 24 months at -20 degrees C plus or minus 5 degrees C, and on this article that assignment is confirmed against the resolved sequence before it is printed: the EDP candidate contains an Asp-Pro bond, the single most acid-labile linkage in peptide chemistry, which makes the stability-indicating method non-generic. The limiting attribute is therefore the cleavage product of the labile bond the resolved sequence carries, the degradation pathway being a function of the sequence, and the interval is set on real-time and accelerated data for that attribute, shortened on data and never extended without a completed dataset.