D-cycloserine

CHEBI:40009 ·resolve ·ANTIMYCOBACTERIAL ·EXACT REVIEWED

A 4-amino-1,2-oxazolidin-3-one that has R configuration. It is an antibiotic produced by Streptomyces garyphalus or S. orchidaceus and is used as part of a multi-drug regimen for the treatment of tuberculosis when resistance to, or toxicity from, primary drugs has developed. An analogue of D-alanine, it interferes with bacterial cell wall synthesis in the cytoplasm by competitive inhibition of L-alanine racemase (which forms D-alanine from L-alanine) and D-alanine—D-alanine ligase (which incorporates D-alanine into the pentapeptide required for peptidoglycan formation and bacterial cell wall synthesis). — ChEBI

Classification

cycloserine-like antibioticARO:3007154

Strictly broader compounds or drug classes this molecule belongs to.

Label unavailable CHEBI:23503
organonitrogen heterocyclic antibiotic CHEBI:25558
Label unavailable CHEBI:25807
cycloserine-like antibiotic ARO:3007154

Chemical structure

Computed structure properties
Molecular formula	C3H6N2O2
Charge	0
Average mass	102.093 Da
Monoisotopic mass	102.04293 Da
Source	ChEBI
InChIKey	DYDCUQKUCUHJBH-UWTATZPHSA-N

SMILES

[H][C@@]1(N)CONC1=O

InChI

InChI=1S/C3H6N2O2/c4-2-1-7-5-3(2)6/h2H,1,4H2,(H,5,6)/t2-/m1/s1

Also called

Seromycin (BRAND_NAME)— chebi
cicloserina (INN)— chebi
cycloserine (INN)— chebi
cycloserinum (INN)— chebi
cyclosérine (INN)— chebi
(4R)-4-aminoisoxazolidin-3-one (EXACT_SYNONYM)— chebi
(+)-4-amino-3-isoxazolidinone (EXACT_SYNONYM)— chebi
(+)-cycloserine (EXACT_SYNONYM)— chebi
(R)-4-AMINO-ISOXAZOLIDIN-3-ONE (EXACT_SYNONYM)— chebi
D-(+)-cycloserine (EXACT_SYNONYM)— chebi
D-4-amino-3-isoxazolidinone (EXACT_SYNONYM)— chebi
D-4-amino-3-isoxazolidone (EXACT_SYNONYM)— chebi
D-Cycloserine (EXACT_SYNONYM)— chebi
DCS (EXACT_SYNONYM)— chebi
PA 94 (EXACT_SYNONYM)— chebi
PA-94 (EXACT_SYNONYM)— chebi
Ro-1-9213 (EXACT_SYNONYM)— chebi
cyclo-D-serine (EXACT_SYNONYM)— chebi
orientomycin (EXACT_SYNONYM)— chebi
α-Cycloserine (EXACT_SYNONYM)— chebi

Cross-references

Identifiers for this same structure in other resources. An accession that lands on two different structures in this corpus is withheld from both rather than shown here, since it names at most one of them.

Drug registries

Identifiers that name a drug rather than a structure. One of these can cover a parent compound, its salts and its stereoisomers, which this corpus keeps as separate records, so it is not an equivalence of structure.

Patents and articles

Documents about this compound. A patent covers a class and an article covers a topic; neither identifies a structure.

Activity roles

Every antimicrobial role a source asserts for this compound — the unreduced evidence behind its antimicrobial_class.

antitubercular agent CHEBI:33231
antimicrobial agent CHEBI:33281

Source concepts

Every upstream concept that resolved to this record. The merge is the product: this is what shows ChEBI and CARD are describing the same structure.

Upstream concepts merged into this record
Source	Native ID	Label	Minted CURIE	Version
ARO	`ARO:3000760`	cycloserine	`antibioticmech:aro-000a78a459`	2026-08-30
CHEBI	`CHEBI:40009`	D-cycloserine	`antibioticmech:chebi-0c70ed4cf2`	2026-08-30

Related pathway records

Evidence-qualified relationships to a pinned corpus revision.

PathwayMech: WikiPathways:WP5060TARGETS_PATHWAY_COMPONENT
PMID:4555420 reports inhibition of E. coli alanine racemase by D-cycloserine. The linked E. coli pathway contains alanine racemase. The experiment used E. coli W; this is an enzyme/process correspondence, not strain identity.
Source revision: aa305727458c44ab05614901334540e2c87a9f3a

Molecular targets

The molecular entity or process this compound acts on. Each target carries evidence — this is a mechanistic claim, not a classification.

cycloserine sensitive alr PROTEIN DIRECT_BINDING_TARGET

ARO:3000722

CARD/ARO database assertion; target organism, strain, and assay are not specified. Alanine racemase is asserted as the cycloserine-sensitive enzyme. Evidence status: PRIMARY_EVIDENCE_NEEDED. Source: CARD_ARO 2026-08-30 (retrieved 2026-08-30).

ARO:3000722 (CARD/ARO asserts targeted_by_antibiotic ARO:3000760 (cycloserine); database assertion, not a primary citation.)

cycloserine sensitive D-alanine synthetase PROTEIN DIRECT_BINDING_TARGET

ARO:3000723

CARD/ARO database assertion; target organism, strain, and assay are not specified. D-alanine ligase is asserted as the cycloserine-sensitive enzyme. Evidence status: PRIMARY_EVIDENCE_NEEDED. Source: CARD_ARO 2026-08-30 (retrieved 2026-08-30).

ARO:3000723 (CARD/ARO asserts targeted_by_antibiotic ARO:3000760 (cycloserine); database assertion, not a primary citation.)

alanine racemase PROTEIN MEASURED_TARGET_ASSOCIATION

Purified E. coli W alanine racemase kinetics showed competitive inhibition by D-cycloserine with Ki 6.5e-4 M; no direct binding measurement or compound-bound structure was reported. Evidence status: PRIMARY_EVIDENCE. Source: PRIMARY_LITERATURE 1972-06 (retrieved 2026-09-02).

Escherichia coli NCBITaxon:562

PMID:4555420 (Primary D-cycloserine alanine-racemase kinetic study (DOI:10.1128/JB.110.3.978-987.1972).)

Mechanism summary

Mode of action: CELL_WALL_SYNTHESIS_INHIBITION microbial target — CURATOR: PMID:4555420 measured competitive inhibition of Escherichia coli W alanine racemase by exact D-cycloserine, with Ki 6.5e-4 M. This supports depletion of D-alanine for peptidoglycan synthesis. The retained CARD assertion for D-alanine--D-alanine ligase is mechanistically plausible but was not independently upgraded by the primary study inspected here.
Clinical status: APPROVED

Activity spectrum

Measured or curated activity against specific taxa. A number without a method is not an observation — every row here carries an assay.

7 observations · Browse all observations · Complete record (JSON.gz)

Activity observations
Organism	Activity	MIC	Disk diffusion	Assay	Strain	Sample/genome	Evidence
Mycobacterium tuberculosis complex	RESISTANT	—	—	CRyPTIC DST; SEQTREAT2020; liquid media; MGIT; MGIT960; critical concentration UK mg/L	—	7 source isolates 7 measurements	Evidence Page data (JSON.gz)
Mycobacterium tuberculosis complex	RESISTANT	—	—	CRyPTIC DST; SEQTREAT2020; liquid media; MGIT; MGIT960; critical concentration WHO mg/L	—	4 source isolates 4 measurements	Evidence Page data (JSON.gz)
Mycobacterium tuberculosis complex	SUSCEPTIBLE	—	—	CRyPTIC DST; SEQTREAT2020; liquid media; MGIT; MGIT960; critical concentration WHO mg/L	—	13 source isolates 13 measurements	Evidence Page data (JSON.gz)
Mycobacterium tuberculosis complex	—	—	—	CRyPTIC DST; SEQTREAT2020; liquid media; MGIT; MGIT960; critical concentration WHO mg/L	—	521 source isolates 521 measurements	Evidence Page data (JSON.gz)
Mycobacterium tuberculosis complex	RESISTANT	—	—	CRyPTIC DST; SEQTREAT2020; solid media; LJ; critical concentration WHO mg/L	—	22 source isolates 22 measurements	Evidence Page data (JSON.gz)
Mycobacterium tuberculosis complex	SUSCEPTIBLE	—	—	CRyPTIC DST; SEQTREAT2020; solid media; LJ; critical concentration WHO mg/L	—	1301 source isolates 1301 measurements	Evidence Page data (JSON.gz)
Mycobacterium tuberculosis complex	—	—	—	CRyPTIC DST; SEQTREAT2020; solid media; LJ; critical concentration WHO mg/L	—	279 source isolates 279 measurements	Evidence Page data (JSON.gz)

Resistance mechanisms

3 source-backed resistance determinants or associations, with ARO grounding where reported. Grouped by reported mechanism type.

ANTIBIOTIC_TARGET_ALTERATION 3

ANTIBIOTIC_TARGET_ALTERATION
Determinant	ARO ID	Organism	Gene families	Evidence
Mycobacterium tuberculosis ald mutations confer resistance to cycloserine	ARO:3004945	not organism-specific	—	ARO:3004945 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000760 (cycloserine); database assertion, not a primary citation.)
Mycobacterium tuberculosis alr with mutation conferring resistance to cycloserine	ARO:3004947	not organism-specific	—	ARO:3004947 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000760 (cycloserine); database assertion, not a primary citation.)
Mycobacterium tuberculosis ddlA mutations confer resistance to cycloserine	ARO:3004941	not organism-specific	—	ARO:3004941 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000760 (cycloserine); database assertion, not a primary citation.)

Record-level evidence

PMID:4555420 (Primary exact-D-cycloserine alanine-racemase inhibition study.)

Curation history

SEEDED_FROM_SOURCES 2026-08-30 · seed_from_sources
Seeded from data/raw/ inventories (ARO, CHEBI)
RESEEDED_FROM_SOURCES 2026-08-30 · seed_from_sources
Re-seeded from updated data/raw/ inventories
RESEEDED_FROM_SOURCES 2026-08-30 · seed_from_sources
Re-seeded from updated data/raw/ inventories
RESEEDED_FROM_SOURCES 2026-08-31 · seed_from_sources
Re-seeded from updated data/raw/ inventories
RESEEDED_FROM_SOURCES 2026-08-31 · seed_from_sources
Re-seeded from updated data/raw/ inventories
RESEEDED_FROM_SOURCES 2026-08-31 · seed_from_sources
Re-seeded from updated data/raw/ inventories
REVIEWED 2026-09-03 · codex · LLM-assisted
Verified exact ChEBI/CARD stereochemical identity, structure, antimycobacterial roles, class, FDA provenance, and retained CARD target and resistance assertions; added cell-wall synthesis inhibition and primary alanine-racemase kinetics while preserving the ligase-evidence gap.
RESEEDED_FROM_SOURCES 2026-09-10 · seed_from_sources
Re-seeded from updated data/raw/ inventories
RESEEDED_FROM_SOURCES 2026-09-26 · seed_from_sources
Re-seeded; changed: activity_spectrum (CRYPTIC 3.4.0). Upstream retrieval date 2026-08-30, unchanged.
RESEEDED_FROM_SOURCES 2026-10-05 · seed_from_sources
Re-seeded; changed: activity_membership_collections (CRYPTIC 3.4.0). Upstream retrieval date 2026-08-30, unchanged.
ADD_PATHWAY_LINKS 2026-10-05 · codex · LLM-assisted
Added reviewed PathwayMech relationships and any supported protein example from curation/pathway_links.yaml; organism and evidence limits are recorded in each basis.

Provenance

Seeded by scripts/seed_from_sources.py from the committed inventories in data/raw/. View the record (YAML).

Explore across X-Mech: MediaIngredientMech (D-cycloserine) · CultureMech · NaturalProductMech · PathwayMech · TraitMech