glycine
Enable an agent to identify glycine, assess the condition and suitability of a particular material, and determine which uses or handling actions its evidence supports.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
recalled by Codex without web access - no source was read
Researched by: Codex
Purpose and description
Enable an agent to identify glycine, assess the condition and suitability of a particular material, and determine which uses or handling actions its evidence supports.
Glycine is the achiral α-amino acid NH₂CH₂COOH, the simplest proteinogenic amino acid, which occurs predominantly as a zwitterion in its crystalline form and in aqueous solution near neutral pH.
It can be Resolve a material label to glycine and flag evidence suggesting a salt, derivative or mixture.; Compare a lot's assay and contaminants against a named intended-use specification.; Calculate glycine quantities for solution preparation using the documented assay and moisture basis.; Interpret solution charge states and solid-form measurements under recorded conditions.; Select storage and handling actions supported by the lot's documentation and applicable requirements.; Hold or reject material when identity, quality or intended-use evidence is insufficient..
Distinguishing features
Glycine has the connectivity NH2-CH2-COOH and molecular formula C2H5NO2; formula matching alone does not establish this connectivity.
Its alpha carbon bears two hydrogen atoms, so glycine lacks the alpha-carbon stereocentre found in other standard proteinogenic amino acids.
Sarcosine has an N-methyl group and alanine has an alpha-carbon methyl group; neither is glycine.
Free glycine must be distinguished from a glycine residue incorporated into a peptide through covalent bonds.
A material containing a glycine-derived ion and a counterion must be distinguished from glycine itself and from ordinary pH-dependent speciation in solution.
Scope
+ Molecular identity, chemical identifiers and distinctions from glycine salts, derivatives and residues
+ Lot-specific glycine content, impurities, moisture and documented grade
+ Solid form, solution speciation and physical properties under stated conditions
+ Biochemical roles that affect recognition and intended-use suitability
+ Evidence governing storage, handling, hazards and permitted material uses
- Finished supplements, medicines, foods and cosmetic formulations containing glycine
- Manufacturing processes and their equipment, except their effects on material quality
- Proteins and peptides containing covalently bound glycine residues
- Glycine salts, metal complexes and chemically modified derivatives as independent substances
- Clinical treatment protocols, dosing recommendations and claims of therapeutic efficacy
Characteristics
- Chemical identity
- Aminoacetic acid; C2H5NO2; verified structure and identifier mappings Prevents substitution with similarly named amino acids, derivatives or salts.
- Glycine assay
- % mass fraction, with analytical method and as-received or dry-basis designation Determines actual glycine content and whether a lot meets its intended specification.
- Water content
- % mass fraction, with method; distinguish water measurement from loss on drying Affects assay interpretation, weighing and material acceptance.
- Impurity profile
- Named impurities in mg/kg or % mass fraction, with detection limits and methods An overall assay does not identify contaminants that can disqualify a lot.
- Physical and crystalline form
- Solid or dissolved; alpha, beta, gamma, mixed or unverified crystalline form where applicable Form affects interpretation of diffraction, thermal behaviour and processing observations.
- Solution conditions
- Glycine concentration in mol/L or g/L; pH; temperature in °C; solvent and ionic strength Charge-state distribution and solubility cannot be assessed without the solution conditions.
- Thermal behaviour
- Transition or decomposition temperature in °C, with method, atmosphere and heating rate Prevents a decomposition event from being treated as an ordinary melting or boiling point.
- Grade and conformance
- Supplier-declared grade; named specification and edition; tested, conforming, nonconforming or unverified Chemical identity alone does not establish suitability for food, pharmaceutical or analytical use.
- Material provenance
- Supplier, manufacturer, lot, certificate of analysis and linked test reports Connects suitability decisions to the specific material and supporting evidence.
- Hazard and regulatory assessment
- Jurisdiction, assessment date, applicable SDS, classification and exposure-limit status Distinguishes verified handling requirements from assumptions based on glycine's biological occurrence.
Also called
Where this came from
wikidata · CC0 1.0
Also registered as vr.tr.glycine
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 6 bundles · 11 layers · 19 findings · 29 questions.
Glycine identity Establish what counts as glycine and resolve its identifiers without extending the entry to neighbouring substances.
Glycine appears as a free amino acid, a solution species, a peptide residue and part of named salts; these require explicit boundaries.
Molecular recognition
Recognise aminoacetic acid by structure and supporting identity evidence.
Aminoacetic acid identity
Record the connectivity NH2-CH2-COOH, formula C2H5NO2 and absence of an alpha-carbon stereocentre as identity criteria.
- Does the reported structure establish aminoacetic acid rather than sarcosine, alanine or another compound? definition
- Which authoritative records verify the CAS number, PubChem CID and EC number for this exact chemical identity? provenance
Free glycine boundaries
Separate glycine material from covalently bound residues, derivatives and separately identified salts.
Species and substance boundary
Distinguish pH-dependent protonation of dissolved glycine from a separately supplied salt or complex, and free glycine from peptide-bound residues.
- Does the material contain free glycine, a glycine salt or complex, or covalently bound glycine residues? boundary
- Does the analytical result measure free glycine or total glycine released by sample hydrolysis? measurement
Glycine lot quality Represent the composition and acceptance evidence of a particular glycine lot.
Two materials labelled glycine can differ in water, contaminants and verified suitability despite sharing molecular identity.
Assay and contaminants
Establish glycine content and the impurities relevant to the intended use.
Interpretable composition
Record assay basis, water measurement and separately measured contaminants so a purity claim can support material decisions.
- What is the glycine assay, by which method, and is it reported on an as-received or dry basis? measurement
- Which amino-acid impurities, residual processing chemicals, elemental contaminants or microbial attributes require separate testing for this use? action
Grade and lot evidence
Connect grade claims to an explicit specification and the supplied lot.
Documented conformance
Treat food, pharmaceutical, reagent and other grade descriptions as claims requiring their own acceptance evidence.
- Which named specification and edition define the claimed glycine grade? definition
- Does the certificate of analysis identify this lot and substantiate every acceptance criterion needed for its intended use? provenance
Glycine physical state Describe crystalline glycine and dissolved glycine using properties tied to measurement conditions.
Glycine's crystal form, ionic character and thermal decomposition make unqualified property values inadequate.
Crystals and thermal events
Identify solid form and distinguish phase transitions from decomposition.
Verified solid form
Allow alpha, beta, gamma, mixed and unverified form assignments only at the level supported by the sample evidence.
- Which diffraction or other validated measurements support the assigned glycine polymorph? measurement
- Does a reported thermal temperature describe melting, a solid-state transition or decomposition, and under what measurement conditions? measurement
Dissolution and speciation
Represent glycine concentration, solubility and protonation under explicit solution conditions.
Condition-dependent solution state
Record solvent, temperature, pH and ionic environment before interpreting glycine's dissolved amount or charge-state distribution.
- What solvent, temperature and concentration define the solution, and is undissolved glycine present? measurement
- Which supported acid-dissociation data apply to estimating cationic, zwitterionic and anionic glycine under these conditions? provenance
Glycine biochemical context Capture biological relationships needed to interpret glycine measurements and material-use claims.
Glycine's roles as a protein constituent, metabolic participant and signalling molecule can otherwise be confused with evidence about a supplied product.
Biological pools
Distinguish free glycine measurements from glycine incorporated into biological macromolecules.
Free and incorporated glycine
Relate glycine to protein incorporation and metabolism while retaining the measured pool and biological context.
- Which organism, tissue or sample compartment contains the glycine being described? boundary
- What sample preparation and assay distinguish the free glycine pool from protein-derived glycine? measurement
Role and use evidence
Connect biochemical roles to evidence without turning those roles into unsupported material-use claims.
Biological role interpretation
Record the specific pathway or receptor context behind a glycine role and separately assess evidence for the proposed application.
- Which pathway, receptor or experimental system supports the stated biochemical role of glycine? provenance
- What additional application-specific evidence is required before that role supports the proposed use of this glycine material? action
Glycine handling and use Determine storage, handling and use constraints from the actual material and applicable evidence.
Biological familiarity does not establish powder-handling conditions, lot integrity or permission for a regulated use.
Handling and storage
Assess powder exposure, contamination and deterioration during storage or transfer.
Material-specific handling
Use the supplied material's safety documentation and observed condition to establish handling controls and continued acceptability.
- What controls does the applicable SDS require for glycine dust, eye contact, spills and incompatible conditions? action
- Have packaging damage, moisture exposure, caking or contamination triggered a need to retest this lot? action
Jurisdiction and use status
Separate chemical hazard assessment from permission to use a particular grade in a particular application.
Verified use constraints
Attach hazard classification, exposure-limit findings and application requirements to a jurisdiction, date and exact material identity.
- Which current authoritative sources establish the applicable GHS classification and any glycine-specific or general dust exposure limits? provenance
- Does the intended food, pharmaceutical, laboratory or industrial use require specifications or authorisations beyond this lot's documented grade? action
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
A model that cannot be lined up against existing standards, identifiers and practice cannot be adopted by anyone who already uses them.
Reported evidence
Findings from the breadth pass, kept separate from the structural claims.
Check these first
Recalled without web access and unsourced; every item is a lead to verify.
- This is recalled knowledge, not a researched source review; the sense covered is the chemical substance.
- Check current supplier safety data and applicable jurisdictional rules before assigning a GHS classification, exposure limit or authorized use.
- Verify grade-specific specifications and temperature-dependent physical constants; the listed pKa values are approximate and depend on solution conditions.
- Which of these check these first hold for the sense of glycine this model covers, and on what evidence? provenance
Kinds and varieties
Recalled without web access and unsourced; every item is a lead to verify.
- α-glycine crystalline polymorph
- β-glycine crystalline polymorph
- γ-glycine crystalline polymorph
- Pharmaceutical-grade glycine
- Food-grade glycine
- Reagent-grade glycine
- Which of these kinds and varieties hold for the sense of glycine this model covers, and on what evidence? provenance
Identifiers and schemes
Recalled without web access and unsourced; every item is a lead to verify.
- CAS Registry Number - 56-40-6 - Identity of glycine; does not specify purity or crystalline polymorph.
- PubChem CID - 750 - Compound identifier for glycine.
- EC number - 200-272-2 - European chemical inventory identifier.
- IUPAC nomenclature - 2-aminoacetic acid - Glycine is the retained name; aminoethanoic acid is another systematic name.
- Amino-acid residue codes - Gly; G - Three-letter and one-letter codes used in protein sequences.
- Which of these identifiers and schemes hold for the sense of glycine this model covers, and on what evidence? provenance
Standards and regulation
Recalled without web access and unsourced; every item is a lead to verify.
- United States Pharmacopeia-National Formulary: the United States Pharmacopeial Convention publishes a Glycine monograph specifying pharmaceutical quality requirements.
- Which of these standards and regulation hold for the sense of glycine this model covers, and on what evidence? provenance
Real-world use
Recalled without web access and unsourced; every item is a lead to verify.
- Constituent of proteins, particularly abundant in collagen.
- Metabolic precursor used in the biosynthesis of heme, purines, creatine and glutathione.
- Inhibitory neurotransmitter and co-agonist at NMDA receptors.
- Component of laboratory buffers, including electrophoresis buffers.
- Ingredient in pharmaceutical and food formulations where the relevant grade and permitted use are satisfied.
- Which of these real-world use hold for the sense of glycine this model covers, and on what evidence? provenance
Typical measurements
Recalled without web access and unsourced; every item is a lead to verify.
- Molar mass - 75.07 - g/mol
- First acid dissociation constant, pKa, in water - Approximately 2.34 near 25 °C - dimensionless
- Second acid dissociation constant, pKa, in water - Approximately 9.60 near 25 °C - dimensionless
- Isoelectric point - Approximately 5.97 - pH
- Which of these typical measurements hold for the sense of glycine this model covers, and on what evidence? provenance
Failure modes and hazards
Recalled without web access and unsourced; every item is a lead to verify.
- Airborne powder can cause mechanical irritation of the eyes and respiratory tract.
- Strong heating causes decomposition, so an ordinary boiling point is not an appropriate handling constant.
- Material with unsuitable impurities or microbial contamination may fail food or pharmaceutical specifications despite having the correct chemical identity.
- Changes in crystalline polymorph can affect solid-state properties and processing behavior.
- Which of these failure modes and hazards hold for the sense of glycine this model covers, and on what evidence? provenance
Regional variation
Recalled without web access and unsourced; every item is a lead to verify.
- Food and pharmaceutical uses depend on jurisdiction-specific permissions and quality specifications; chemical identity alone does not establish suitability.
- Which of these regional variation hold for the sense of glycine this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Recalled without web access and unsourced; every item is a lead to verify.
- Alanine - Alanine has a methyl side chain and a stereogenic α-carbon; glycine has hydrogen as its side chain and is achiral.
- Sarcosine - Sarcosine is N-methylglycine, with a methyl group replacing one hydrogen on glycine's amino nitrogen.
- Betaine - In the glycine-betaine sense, it is trimethylglycine with a permanently charged quaternary ammonium group.
- Glycinate salts - These contain deprotonated glycine associated with a counterion or metal; their composition and identifiers differ from glycine itself.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of glycine this model covers, and on what evidence? provenance
What the second pass must settle
- Which authoritative identity records confirm the CAS, PubChem and EC mappings, and does an existing Vercy model already cover glycine?
- Which reference measurements should govern polymorph identification, solubility and thermal behaviour, including whether conventional melting or boiling values are applicable?
- Which acid-dissociation values and activity assumptions are appropriate across the solution conditions this model must support?
- Which grade specifications and impurity limits are required for the intended applications, and which lot-specific records are available?
- What current jurisdiction-specific hazard classifications, exposure limits and use requirements apply to the exact glycine material being assessed?