The KPV tripeptide record is PubChem CID 125672, titled Msh (11-13). PubChem lists CAS 67727-97-3, formula C16H30N4O4 and Molecular Weight 342.43 g/mol for that free-acid structure. These are database identifiers and a calculated value. The KPV product page is a separate document location. To reconcile a KPV name, compare the record identifier, formula, sequence, terminal notation and configuration together; the three letters alone leave information unstated.
This reference concentrates on registry reconciliation. The KPV overview provides broader context, while the sections below preserve the exact fields needed to distinguish a name, a specified structure and an analytical observation. The KPV certificate article covers the document-verification walkthrough.
Which registry record identifies the KPV tripeptide?
PubChem identifies the selected free-acid tripeptide as CID 125672, with the record title Msh (11-13), CAS annotation 67727-97-3 and formula C16H30N4O4. CID means compound identifier, PubChem's numerical key for a compound record. A CAS number is a separate registry identifier; here it is copied from PubChem's dedicated CAS annotations. ChEBI provides another database entry, CHEBI:160254, named Lys-Pro-Val, with the same formula and CAS cross-reference. Preserve the database name beside each key, since a bare number loses the system that gives it meaning. The table separates the two entries rather than merging their names and numerical fields into a synthetic record. Its values come from the cited registry pages. Matching those entries is a comparison of written structures and annotations, with no conclusion about a container or a laboratory sample.
For the free-acid KPV tripeptide, PubChem CID 125672 lists Msh (11-13), CAS 67727-97-3, C16H30N4O4 and Molecular Weight 342.43 g/mol. ChEBI's corresponding entry is CHEBI:160254. Keep each identifier attached to its database and compare the sequence and terminal notation as well as the formula. This combination specifies the intended registry record; it supplies no lot-specific observation.
| Registry and record name | Record key / PubChem CID | CAS field | Formula | Printed mass field | Structure described | Source |
|---|---|---|---|---|---|---|
| PubChem: Msh (11-13) | CID 125672 | 67727-97-3 | C16H30N4O4 | Molecular Weight: 342.43 g/mol | L-lysyl-L-prolyl-L-valine, free acid | PubChem PUG View |
| ChEBI: Lys-Pro-Val | CHEBI:160254; corresponding PubChem CID 125672 | 67727-97-3 | C16H30N4O4 | Average Mass: 342.440 | The same named free-acid tripeptide configuration | ChEBI entry |
A useful transcription keeps the source's field names intact. For example, enter PubChem's title in a record-title column and its CAS annotation in a CAS column. Replacing either with the search phrase KPV would discard information that can distinguish the intended structure from an ambiguous label.
Why is the name KPV alone not a registry match?
A KPV name lookup does not, by itself, specify the structure intended by the reader. PubChem's synonym response for the selected tripeptide includes several differently written names, including terminal and acetate wording, so a returned name needs examination alongside the actual record fields. A contributed synonym is a name associated with an entry; it is not a substitute for that entry's formula, systematic name or terminal description. The practical answer is to inspect the candidate entry rather than infer identity from the query that found it. Compare the candidate's CID, CAS annotation, formula and sequence with the selected tripeptide record. If one field is absent or different, write down that specific gap instead of silently carrying the KPV label across to the candidate.
The text KPV is a search label, while a registry match depends on several fields agreeing. PubChem's tripeptide synonym list illustrates that names can carry different levels of structural detail. Check the candidate's record key, formula, CAS annotation and terminal sequence. A familiar name in a search result cannot resolve a missing structural field.
| Candidate information | Comparison to make | Transcription if incomplete |
|---|---|---|
| Only the letters KPV | Find the database key and the structure fields | Candidate record remains unselected |
| A record key but no terminal notation | Read the candidate's structural description | Termini not specified in the excerpt |
| Matching formula with configuration unstated | Compare the full systematic name | Configuration needs a separate check |
| An acetate name beside a peptide formula | Determine which entity each field describes | Counterion and composition unresolved |
Use the PubChem synonym response as a list of associated names, keeping its role separate from the structured fields in PUG View.
How are lysine proline valine and KPV written as a sequence?
KPV expands to lysine, proline and valine in that order: K, P and V are the one-letter residue symbols. The corresponding three-letter sequence is Lys-Pro-Val. IUPAC/IUB's one-letter notation and peptide-symbolism guidance supply the reading convention, from the amino terminus toward the carboxyl terminus, conventionally left to right. A terminus is an end of the written chain. PubChem's selected record includes H-Lys-Pro-Val-OH, which makes terminal information visible beside the residue order. The initial H and final OH belong to the terminal notation; they are not extra residue symbols. The compact letters therefore communicate less than the expanded terminal expression. Preserve both when copying an identifier for comparison, and keep the stated configuration alongside them. The table gives each spelling its own purpose without substituting one spelling for every structural field.
KPV is the one-letter sequence for Lys-Pro-Val: lysine followed by proline followed by valine. PubChem's free-acid record also supplies H-Lys-Pro-Val-OH and L-lysyl-L-prolyl-L-valine. The first expression makes the terminal notation explicit; the second spells out L configuration. IUPAC/IUB notation reads the chain from its amino end toward its carboxyl end. Copy terminal and configuration details with the compact sequence.
| Representation | What the reader can preserve | Information to keep beside it |
|---|---|---|
| KPV | Compact residue order: lysine, proline, valine | Selected registry entry, terminal description and configuration |
| Lys-Pro-Val | Three-letter residue order | Explicit end groups when the document supplies them |
| H-Lys-Pro-Val-OH | Residue order with terminal H and OH notation | The full source record and its configuration |
| L-lysyl-L-prolyl-L-valine | Residue names with L configuration stated | Record key and formula for reconciliation |
The spellings are documented in PubChem's tripeptide record; the reading rules come from one-letter notation, residue symbols and peptide symbolism. The KPV structural article covers the longer structural comparison.
What does the record specify about configuration?
The selected KPV record specifies L configuration in its residue names and three (2S) descriptors in its systematic name. Configuration describes the spatial arrangement recorded for the structure. The formula counts atoms but does not encode that arrangement, so a formula match cannot replace a configuration check. IUPAC/IUB's residue-symbol guidance says that three-letter amino-acid symbols ordinarily denote L configuration unless otherwise specified. That convention helps read a written sequence; it supplies no measurement of a sample. PubChem and ChEBI print the complete systematic name reproduced below. Keeping it intact avoids losing a descriptor while shortening a name for a table or a spreadsheet. A comparison can preserve the complete name in one field and the shorter all-L description in another, with the source attached to both entries for later comparison.
In a teaching transcription check, mark each of the three (2S) strings on the source and then on the copied name. Compare punctuation and residue naming separately. This is a check on the fidelity of the transcription, with no analytical conclusion attached. If a document supplies only a formula, record configuration as unstated in that document, even when a separate reference entry provides more detail.
ChEBI's Lys-Pro-Val entry and PubChem PUG View supply the recorded name; IUPAC/IUB residue-symbol principles explain the written configuration convention.
Which KPV synonyms need additional form checks?
Names that add terminal, parent-sequence or acetate wording deserve separate fields in a KPV record comparison. PubChem lists L-Lysyl-L-prolyl-L-valine and ACTH-(11-13), as well as H-Lys-Pro-Val-OH AcOH and an acetate-salt name. These are associated name strings, and their presence does not change the entry's displayed formula into a salt-inclusive formula. Parent-sequence labels identify a naming relationship; they do not specify a sample's origin or provide missing terminal details. For a reliable transcription, copy the synonym exactly into a name-as-written field and place the registry's structured formula and sequence elsewhere. A conflict or omission then remains visible instead of disappearing during editorial cleanup.
| Name as PubChem prints it | Documentation question left to resolve |
|---|---|
| L-Lysyl-L-prolyl-L-valine | Does the copied record retain its terminal description? |
| ACTH-(11-13) | Which explicit tripeptide structure accompanies this parent-sequence label? |
| H-Lys-Pro-Val-OH AcOH | Where are counterion composition and the entity's formula specified? |
| H-LYS-PRO-VAL-OH ACETATE SALT | Is there a separately specified salt record and composition? |
These strings come from the PubChem synonym list. In a teaching comparison, an exact copied synonym can coexist with an unresolved form field. Do not remove AcOH from the copied name to make it resemble the peptide-only entry, and do not add acetate to the formula because the synonym contains that word. Both changes would replace source transcription with an unsupported interpretation.
Why do PubChem and ChEBI print different molecular weights?
PubChem prints Molecular Weight 342.43 g/mol for its KPV tripeptide entry, while ChEBI prints Average Mass 342.440 for Lys-Pro-Val. Both records give C16H30N4O4. The source displays establish a difference in the printed values and their decimal precision, but the cited records do not establish the computational cause. Decimal precision means how many digits a source displays after the decimal point; it does not establish the accuracy of a laboratory observation. Preserve each field label and value exactly, with its database name, rather than silently replacing one with the other.
Teaching check: arithmetic on printed database values only ChEBI Average Mass 342.440 PubChem Molecular Weight 342.43 Printed-value subtraction: 342.440 - 342.43 = 0.010 This difference does not identify a calculation method or sample property.
The subtraction makes the discrepancy explicit without explaining it. It supplies no reason to infer a counterion, a different terminal group or a correction to either database. Those explanations would need their own supporting record. Keep a separate discrepancy note reading calculation basis unresolved rather than forcing the two source columns to agree.
The comparison uses PubChem's Molecular Weight field and ChEBI's Average Mass field. Neither printed value is an observed mass for a Glow lot.
What additional information does KPV acetate require?
KPV acetate needs a specified counterion and composition before a salt-inclusive formula or molecular weight can be assigned. A counterion is the accompanying ion in a salt; stoichiometry states the relative numbers of components represented by a formula. PubChem's associated names include acetate wording, but those names alone do not establish a peptide-to-counterion ratio for the displayed tripeptide record. They also cannot supply a new salt identifier. Keep the peptide entry, the copied acetate name and any separately documented salt entry in distinct fields. That arrangement allows an unanswered composition question to remain visible. The sources cited here give no numerical acetate composition.
What does an identity measurement compare for a tripeptide?
A tripeptide identity comparison relates an observation to the expected structure of a named registry record. Preserve the sequence, terminal groups, configuration, form, mass-field convention and any stated ion or charge interpretation. PubChem's molecular weight is a calculated reference field, not a laboratory observation. Without a specified observation and its comparison basis, the record alone supports no conclusion about a sample.
Method background is in the HPLC and mass spectrometry guide. Glow lists lot documents on the KPV product page; each document applies to its own lot. KPV Capsules is a separate product with separate lot records. For mass conventions, see the glutathione chemistry reference.
KPV is a research reference material. Check lot-specific document availability and the reported methods and findings.
View KPV on the store →Frequently asked questions
What is the KPV CAS number?
PubChem lists 67727-97-3 in the CAS annotations for CID 125672, titled Msh (11-13); ChEBI lists the same number for CHEBI:160254, Lys-Pro-Val. Copy the registry source beside the number. In a comparison, a CAS match is one completed comparison, while formula, residue order, terminal notation and configuration still need their own entries. An absent field in another document remains absent even when its CAS string matches the selected entry.
Why is a KPV name search not enough to identify the record?
A short search phrase does not carry all the structural information needed for a registry match. PubChem's associated-name list for the tripeptide contains several spellings with different amounts of detail. If a candidate entry is unclear, record its key and compare the structural fields directly. Keep a failed or incomplete match as a documented question rather than selecting by name alone.
Why do PubChem and ChEBI print 342.43 and 342.440?
Those are the respective printed Molecular Weight and Average Mass values for the corresponding KPV entries. The available source evidence does not resolve their calculation basis. Extra displayed decimal places alone do not explain the last-digit disagreement. When choosing a reference, name the database and field that supplied it rather than averaging the values or silently replacing one.
Does an acetate synonym establish a salt's molecular weight?
No. PubChem's acetate wording is an associated name, which does not supply a complete salt composition or a separate salt identifier. A salt-inclusive molecular weight requires a specified entity with documented counterion composition and stoichiometry. If those details are missing, retain the acetate name exactly and mark the composition question unresolved. Copying the peptide-only numerical field into a salt column would hide the missing information rather than resolve it.
Does the sequence KPV specify termini and configuration completely?
The compact sequence gives residue order, but a full reconciliation should preserve terminal and configuration information explicitly. PubChem supplies H-Lys-Pro-Val-OH and L-lysyl-L-prolyl-L-valine for the selected entry. IUPAC/IUB notation conventions help interpret those strings; they do not establish what an analyzed sample contains. If a short document gives only KPV, record exactly that partial description. A separate reference may identify the intended structure, but its additional fields should remain attributed to that reference.
Sources and scope notes
Registry fields and nomenclature references follow the sources cited below, read October 15, 2026, Pacific. PubChem's recorded modification date is September 26, 2026; ChEBI's is March 20, 2025. Those dates describe the entries rather than the date of a sample observation.
The printed-value subtraction is editorial arithmetic. The cause of the PubChem and ChEBI mass difference and any acetate composition are outside the cited sources. No KPV lot document is included.
- NIH/NLM PubChem PUG View, CID 125672, Msh (11-13) Registry title, CAS annotations, formula, sequence, systematic name and mass-field distinctions.
- NIH/NLM PubChem PUG REST, CID 125672 synonyms Associated names, including acetate wording; no salt-composition determination.
- EMBL-EBI ChEBI, CHEBI:160254, Lys-Pro-Val Formula, Average Mass, systematic name and CAS cross-reference.
- IUPAC/IUB nomenclature, one-letter amino-acid notation Residue symbols, sequence direction and notation limits.
- IUPAC/IUB nomenclature, residue-symbol principles Three-letter symbols, configuration conventions and hyphens.
- IUPAC/IUB nomenclature, peptide symbolism Chain direction, configuration and charge notation.