The name TB-500 can point to two different PubChem records. CID 62707662 lists TB-500 among its synonyms and prints CAS 885340-08-9, Ac-LKKTETQ-OH, C38H68N10O14 and 889.0 g/mol. Full-length thymosin beta-4, recorded as Timbetasin, is CID 16132341: CAS 77591-33-4, 43 residues, C212H350N56O78S and 4963 g/mol. A document's formula and mass fields, not the name, show which record it means. These are database descriptions, not an assignment of either record to Glow material. The TB-500 product page provides the product reference; this page compares registry fields and the document codes attached to one lot record.
The blog post on what TB-500 is covers the broader naming discussion; the numerical comparison below stays separate. For the established overview, see the TB-500 guide. Here, a compound identifier, abbreviated CID, means PubChem's key for an individual compound record.
Which chemical records distinguish TB-500 and thymosin beta-4?
PubChem files the TB-500 synonyms on CID 62707662, the acetylated seven-residue record at 889.0 g/mol, and files full-length thymosin beta-4 as the 43-residue Timbetasin record, CID 16132341, at 4963 g/mol. PubChem gives each a separate CID. A molecular formula lists the elements and their atom counts in the represented entity; the printed molecular weight accompanies that representation. The table therefore keeps the record title beside both numbers. It also identifies the dedicated CAS field separately from names deposited as synonyms. A shared formula can leave a stereochemical distinction unresolved, while a salt representation can carry a different formula. Read across a complete row before comparing columns between rows.
| Record title | PubChem CID | Dedicated CAS field | Formula | Printed molecular weight, g/mol | Represented form | Source |
|---|---|---|---|---|---|---|
| Timbetasin | 16132341 | 77591-33-4 | C212H350N56O78S | 4963 | Full 43-residue N-acetylated reference, defined L stereochemistry | PubChem Timbetasin |
| Thymosin Beta 4 | 45382195 | None listed | C212H350N56O78S | 4963 | Full-length record, stereochemistry unspecified | PubChem Thymosin Beta 4 |
| Unii-qhk6Z47gtg | 62707662 | 885340-08-9 | C38H68N10O14 | 889.0 | N-acetylated seven-residue reference associated with TB-500 synonyms | PubChem acetylated heptapeptide |
| TB 500 Trifluoroacetic Salt | 169446757 | None listed | C40H69F3N10O16 | 1003.0 | Trifluoroacetic acid salt representation | PubChem salt record |
TB-500 is a synonym on PubChem CID 62707662, the acetylated seven-residue record (CAS 885340-08-9, C38H68N10O14, 889.0 g/mol). Thymosin beta-4 is the 43-residue Timbetasin record, CID 16132341 (CAS 77591-33-4, 4963 g/mol). A document using the TB-500 name may print either record's formula and mass, so read those fields on the document itself.
Which CAS numbers belong to the individual records?
The dedicated CAS annotations in the cited PubChem records list 885340-08-9 for the acetylated heptapeptide and 77591-33-4 for Timbetasin. CAS registry numbers and PubChem CIDs are separate identifier systems, so each number needs its own label. The other two rows have no dedicated CAS value listed in the specified records. A synonym is a name or string associated with a record by a depositor; its placement differs from a dedicated annotation. Keeping the field location prevents a familiar-looking string from acquiring more authority during transcription than the source gave it. The record title, field name and value belong together even when a search begins with only a short compound name.
- PubChem CID 62707662: dedicated CAS annotation 885340-08-9; TB500, TB-500 and TB 500 appear among its deposited synonyms.
- PubChem CID 16132341: dedicated CAS annotation 77591-33-4; Timbetasin [USAN] appears among its synonyms.
- PubChem CIDs 45382195 and 169446757: record the CAS field as none listed rather than supplying a number from another row.
Teaching example: a document supplies the name TB-500 but no registry reference. Enter the name as supplied, leave the CID and the CAS-field status unresolved, and record the missing source. Finding a familiar synonym later supplies a candidate record to compare; it does not fill every other field automatically.
How are the full and seven-residue sequences written?
The cited sequence records distinguish a full 43-residue reference from a seven-residue reference while retaining the groups printed at both ends. A residue is one amino acid unit within the written peptide chain. IUPAC/IUB peptide symbolism supplies three-letter abbreviations, and its one-letter notation provides a compact way to write the same order. Ac denotes an acetyl group at the amino end, also called the N-terminus; the ending -OH records the carboxyl end in these source notations. Neither end marker is another residue. PubChem's Timbetasin record supplies the full sequence, while its TB-500-associated record supplies the short sequence. The table carries their source links with the notation, because a detached string of letters can omit terminal information or become separated from its record. Compact transcription should preserve these distinctions rather than saving space by dropping the ends.
| Reference and source | Three-letter notation | Compact notation retaining termini |
|---|---|---|
| Timbetasin, PubChem CID 16132341 | Ac-Ser-Asp-Lys-Pro-Asp-Met-Ala-Glu-Ile-Glu-Lys-Phe-Asp-Lys-Ser-Lys-Leu-Lys-Lys-Thr-Glu-Thr-Gln-Glu-Lys-Asn-Pro-Leu-Pro-Ser-Lys-Glu-Thr-Ile-Glu-Gln-Glu-Lys-Gln-Ala-Gly-Glu-Ser-OH | Ac-SDKPDMAEIEKFDKSKLKKTETQEKNPLPSKETIEQEKQAGES-OH |
| Acetylated heptapeptide, PubChem CID 62707662 | Ac-Leu-Lys-Lys-Thr-Glu-Thr-Gln-OH | Ac-LKKTETQ-OH |
Ac-LKKTETQ-OH is the compact notation for the acetylated seven-residue reference on PubChem CID 62707662. Read its residues as Leu-Lys-Lys-Thr-Glu-Thr-Gln. Ac retains the N-terminal acetyl group and -OH retains the other terminal notation. The bare string LKKTETQ records the residue order but omits the acetyl distinction and the explicit terminal ending.
The IUPAC/IUB peptide symbolism reference explains terminal abbreviations and configuration qualifications; its one-letter notation reference explains the compact alphabet. The accompanying database record still supplies the structural context. For general terminal notation, see the peptide structure reference.
What does acetate wording establish in the synonym list?
Acetate wording in a synonym list establishes that the wording is associated with that record; it does not replace its displayed formula. PubChem CID 62707662 includes TB 500 acetate among its deposited synonyms while displaying C38H68N10O14 and 889.0 g/mol. A record comparison should copy title, formula and component information into separate cells. This prevents an acetate word in a search or title from silently introducing an extra component into a formula that was copied from a different field.
| Source record | Name evidence | Formula and printed molecular weight | Component evidence |
|---|---|---|---|
| PubChem CID 62707662 | TB 500 acetate is a deposited synonym | C38H68N10O14; 889.0 g/mol | The synonym does not rewrite the formula field |
| PubChem CID 169446757 | Title: TB 500 Trifluoroacetic Salt | C40H69F3N10O16; 1003.0 g/mol | Component section identifies CID 62707662 and trifluoroacetic acid CID 6422 |
A salt name and a deposited synonym provide different kinds of record evidence. PubChem CID 62707662 retains its displayed formula despite an acetate synonym. PubChem CID 169446757 supplies a separate TFA salt formula and a component section. Read those fields together before selecting a reference; none of them describes the composition of a Glow lot.
Which formula and components does the TFA salt record list?
The separate record titled TB 500 Trifluoroacetic Salt displays C40H69F3N10O16 and 1003.0 g/mol. TFA abbreviates trifluoroacetic acid. PubChem's component section for the salt record names the short reference and trifluoroacetic acid separately.
Arithmetic on printed values: 1003.0 - 889.0 = 114.0 g/mol. This subtraction compares the two PubChem molecular-weight displays. It is not a measured difference, a separately sourced acid value or a quantity attributable to any certificate.
Why can two full-length records share a formula and molecular weight?
The cited full-length PubChem records share C212H350N56O78S and a molecular weight of 4963 g/mol while differing in stereochemical specification. Stereochemistry describes the spatial arrangement of atoms within a structure. PubChem's Timbetasin entry represents defined L stereochemistry, whereas the entry titled Thymosin Beta 4 leaves stereochemistry unspecified. The formula column cannot express that distinction: it enumerates atoms rather than their spatial arrangement. Likewise, matching printed molecular weights do not resolve information absent from a structural representation. The unspecified entry's DL notation must not become a claim that any material is a characterized mixture. A side-by-side record check can establish that the formula and weight fields agree while leaving the structural descriptions different.
| Field compared | Timbetasin, CID 16132341 | Thymosin Beta 4, CID 45382195 |
|---|---|---|
| Formula | C212H350N56O78S | C212H350N56O78S |
| Printed molecular weight, g/mol | 4963 | 4963 |
| Stereochemical specification | Defined L representation | Unspecified representation |
| Comparison conclusion | Numerical fields match the other row | Spatial specification remains distinct |
Teaching example: a copied reference supplies only the formula and 4963 g/mol. Those fields alone cannot select between these two PubChem entries. Keep the candidate records separate and request the missing structural reference. A more complete name or a cited CID can clarify which entry the document intended without changing either printed number.
Why does the large mass difference help a reference comparison?
PubChem's short and full-length references print widely separated molecular weights, 889.0 and 4963 g/mol, so those displays provide distinct numerical reference points. The useful comparison still requires the represented species and the mass convention. Molecular weight as displayed by PubChem is a computed record property; a monoisotopic mass is a different mass convention and should keep its own label. NIST's SI Guide distinguishes relative molecular mass from molar mass and addresses charge-number qualifications. In a mass-spectrometry document, a mass-to-charge entry cannot simply be relabelled as the neutral molecular weight. A comparison needs the species, charge and convention reported with that entry. This page supplies no observed mass and interprets no analytical finding.
Teaching arithmetic on printed PubChem molecular weights Timbetasin, CID 16132341 4963 g/mol Acetylated heptapeptide, CID 62707662 889.0 g/mol Subtraction: 4963 - 889.0 = 4074.0 g/mol Computed difference of printed values only
The PubChem displays 889.0 and 4963 g/mol give separate reference expectations for the short and full-length entries. Comparing an analytical document with either reference requires the stated species, charge and mass convention. Raw mass-to-charge is not automatically neutral molecular weight. Numerical agreement by itself also leaves sequence and stereochemical details that the comparison may not resolve.
The NIST SI Guide supports the quantity and unit distinctions. Instrument principles belong to the HPLC and mass spectrometry guide. For interpreting identity statements, see the guide to what each testing lab report proves.
Which fields appear in the selected lot documents?
Glow's TB-500 lot documents list vial lot 260312HPTB10, certificate lot 260312-HP-TB10-01 and catalog code TB10. Its certificate has two pages with different accession numbers and paired Search Codes. An accession number identifies a laboratory document entry; Search Code is the laboratory lookup label and should be copied beside its corresponding accession. The issuing laboratory is Freedom Diagnostics, an independent U.S. laboratory. These details locate documents and distinguish their pages. They supply no analytical values here. The selected lot record and TB-500 product page provide the two internal references for this section. The registry comparison elsewhere on this page remains separate from these document identifiers; no CID is assigned to the lot by matching its code.
| Certificate page | Accession Number | Search Code | Dates printed | Printed fields or panels |
|---|---|---|---|---|
| Page 1 | 2603130066 | Glow2603130066 | Received 03/16/2026; reported 03/17/2026 | Labels only; values on the certificate |
| Page 2 | 2603130067 | Glow2603130067 | No additional dates transcribed here | Labels only; values on the certificate |
Ignoring hyphens, the printed lot becomes 260312HPTB1001. Its letters and digits preserve the vial string 260312HPTB10 followed by run suffix 01. Record the original forms and the suffix separately; removing punctuation for comparison does not justify dropping the suffix from the certificate transcription.
The laboratory lookup interface names Search Code, accession and company-name fields. Lookup procedure belongs to the laboratory document guide, while the TB-500 certificate article provides the compound-specific walk-through. For wider document context, use the certificate interpretation guide. Reconciling document identifiers belongs to peptide lot traceability, and the site's quality page describes document availability.
TB-500 is a research reference material. Check lot-specific document availability and the reported methods and findings.
View TB-500 on the store →Frequently asked questions
Which TB-500 record lists CAS 885340-08-9?
PubChem CID 62707662 lists 885340-08-9 in its dedicated CAS annotation and carries the title Unii-qhk6Z47gtg. TB500, TB-500 and TB 500 appear as synonyms on that entry. When documenting the number, retain the CID and the annotation location beside it. If another document supplies only the CAS string, the next question is which record and field its author cited. A matching name or number does not populate the document's unstated sequence, terminal groups or mass convention.
Why can two thymosin beta-4 records share a formula and molecular weight?
PubChem CIDs 16132341 and 45382195 both display C212H350N56O78S and 4963 g/mol, but their structural specification differs. Timbetasin has defined L stereochemistry; the Thymosin Beta 4 entry leaves stereochemistry unspecified. A comparison form should therefore allow separate answers for numerical agreement and structural specification. Marking the formula as matching need not erase the unresolved spatial information. Equally, unspecified stereochemistry on a database record does not establish a characterized mixture in any physical material.
Does an acetate name establish an acetate-containing formula?
An acetate word by itself does not specify the contents of a formula field. PubChem CID 62707662 includes an acetate synonym while displaying C38H68N10O14. Preserve both observations rather than adding atoms to the copied formula. A useful follow-up asks whether the document supplies component information or a separate record reference. PubChem's separately identified TFA salt entry illustrates the kind of additional record detail that can be compared, without establishing a rule that every salt word has equivalent support.
What information disappears when Ac-LKKTETQ-OH is shortened to LKKTETQ?
The seven residue letters remain, but the N-terminal acetyl notation and the explicit carboxyl ending disappear. PubChem's short reference supplies the longer notation, and IUPAC/IUB explains how the terminal markers accompany the residue sequence. In a small table, use a separate terminal-groups column if space prevents keeping the complete string in one cell. Do not assume that an abbreviated sequence elsewhere supplies those missing groups. Record what is explicit and leave the rest as a transcription question.
Which identifiers distinguish the two TB-500 certificate pages?
Page 1 carries accession 2603130066 with Search Code Glow2603130066, and page 2 carries accession 2603130067 with Search Code Glow2603130067. Keep each accession beside its corresponding Search Code and page reference. The vial lot is 260312HPTB10, the certificate lot is 260312-HP-TB10-01 and the catalog code is TB10. These identifiers locate documents; they do not assign a PubChem CID to the lot or supply an analytical finding.
Sources and scope notes
Chemistry entries use the PubChem records cited below, read October 15, 2026. Molecular weights are computed database properties copied at their printed precision. Subtractions are explicitly labelled arithmetic on printed values. Precursor numbering is outside this reference.
Sequence abbreviation explanations use the two IUPAC/IUB references. Quantity and charge qualifications use NIST's SI Guide.
Lot identifiers and field names are transcribed from the TB-500 certificate. No analytical value, composition assignment, authenticity conclusion or lot-release decision is supplied here.
- PubChem CID 16132341, Timbetasin Full-length reference: identifiers, formula, printed molecular weight, sequence and defined stereochemistry.
- PubChem CID 45382195, Thymosin Beta 4 Formula, printed molecular weight, CAS-field status and unspecified stereochemistry.
- PubChem CID 62707662, Unii-qhk6Z47gtg TB-500 synonyms, CAS annotation, formula, printed molecular weight and acetylated seven-residue notation.
- PubChem CID 169446757, TB 500 Trifluoroacetic Salt Salt title, formula, printed molecular weight, CAS-field status and listed components.
- IUPAC/IUB, peptide symbolism Terminal abbreviations and configuration qualifications.
- IUPAC/IUB, one-letter sequence notation Residue-code mapping, orientation and notation limits.
- NIST SI Guide, Chapter 8 Relative molecular mass, molar mass and charge-number terminology.
- Freedom Diagnostics Testing, laboratory lookup interface Search Code, accession and company-name fields.