Follistatin 344 (retired duplicate - resolves to FST(30-344)/FS-315)

1 Identity

Not a distinct molecular class. A numbering convention for the same gene product carried in the merged record. This name resolves to the merged Follistatin FST(30-344) / FS-315 record and describes no separate molecule.

Sequence

No separate sequence exists. '344' is the residue count of the FST-gene precursor, inclusive of the 29-residue signal peptide that is removed on secretion; '315' is the residue count of the same protein as the mature secreted chain, FST(30-344). The two numbers describe one molecule under two conventions - precursor-inclusive and mature - and the difference between them is a signal peptide that no purchasable article contains. A supplier offering 'Follistatin 344' and 'Follistatin 315' as two products is offering one protein twice. Note carefully what '344' does not mean: it does not denote a 344-residue protein in the vial. If a supplier genuinely shipped the uncleaved 344-residue precursor at roughly 38 kDa, that would be a processing failure and not a better article.

Molecular formula

Not established. See the merged record. No formula is written for a glycoform population, and none is written twice.

Average mass

Not established. See the merged record, which states the position: a supplier datasheet reports a predicted 34.7 kDa backbone against an observed 40 to 50 kDa by reducing SDS-page, the gap being the glycan. The specific hazard attaching to this name is that '344' is routinely read as a mass-adjacent number and quoted alongside a molecular weight as though the two were related. They are not: 344 is a residue index.

Monoisotopic mass

Not applicable. See the merged record. No monoisotopic mass is obtainable for a heterogeneously glycosylated 40 kDa protein and none is stated here or anywhere else in this catalog.

Salt / variant note

The variants for this name are held on the merged record. What is specific to this entry is the naming hazard. (1) 'Follistatin 344' against 'Follistatin 315' - one protein, two conventions, routinely sold as two SKUs at two prices. (2) 'Follistatin 344' against FS-288, which IS a different splice form at roughly 31 to 32 kDa backbone and is a genuine substitution risk hiding behind the numbering confusion. (3) 'Follistatin 344' against FS-300, a 301-residue truncated construct sold as a distinct item. A buyer confronting four numbers - 288, 300, 315, 344 - has no way to tell from the numbers alone that two of them are the same molecule and two of them are not. That is the whole reason this name is kept as an entry of its own rather than dropped.

2 Class & testing panel

Form

Single article

Testing panel

P4 — panel definitionby inheritance from the merged record. No panel is assigned to this entry in its own right, because no separate article exists to assign one to

3 Primary sources & evidence

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

None specific to this catalog number, and none is assembled under it. Any literature search must be run against the merged record - UniProt P19883 for identity, and the construct boundary and expression system for the material actually used in a given paper. A citation attached to 'Follistatin 344' as such tells a reader nothing about which construct was studied, which is the same defect this catalog records for FGL and for the DSIP/Emideltide pair: the traded name and the studied article are not reliably the same thing. No statement is made here or in the merged record about what the protein does in any body.

4 Storage & specification

Storage

Not applicable. Nothing is stocked under this catalog number and no storage condition is assigned. The merged record's entry stands for the underlying article: a correctly folded glycosylated protein would require lyophilized, excipient-stabilized presentation at -80 degrees C with a documented freeze-thaw limit, which the current cold chain does not fund.

Shelf life

Not applicable. No material is held under this catalog number, so no retest interval exists and none is published.