methicillin

CHEBI:6827 ·resolve ·ANTIBACTERIAL ·EXACT SEEDED

A penicillin that is 6-aminopenicillanic acid in which one of the amino hydrogens is replaced by a 2,6-dimethoxybenzoyl group. — ChEBI

Machine-generated and unreviewed. Identity, structure and cross-references come straight from ChEBI's and CARD's own data; no curator has signed off on this record yet.

Classification

penicillin beta-lactamARO:3000008

Strictly broader compounds or drug classes this molecule belongs to.

penicillin CHEBI:17334
penicillin allergen CHEBI:88187
penicillin beta-lactam ARO:3000008

Chemical structure

Computed structure properties
Molecular formula	C17H20N2O6S
Charge	0
Average mass	380.422 Da
Monoisotopic mass	380.10421 Da
Source	ChEBI
InChIKey	RJQXTJLFIWVMTO-TYNCELHUSA-N

SMILES

[H][C@]12SC(C)(C)[C@H](C(=O)O)N1C(=O)[C@H]2NC(=O)c1c(OC)cccc1OC

InChI

InChI=1S/C17H20N2O6S/c1-17(2)12(16(22)23)19-14(21)11(15(19)26-17)18-13(20)10-8(24-3)6-5-7-9(10)25-4/h5-7,11-12,15H,1-4H3,(H,18,20)(H,22,23)/t11-,12+,15-/m1/s1

Also called

meticilina (INN)— chebi
meticillin (INN)— chebi
meticilline (INN)— chebi
meticillinum (INN)— chebi
6β-(2,6-dimethoxybenzamido)-2,2-dimethylpenam-3α-carboxylic acid (EXACT_SYNONYM)— chebi
(2S,5R,6R)-6-[(2,6-dimethoxybenzoyl)amino]-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid (EXACT_SYNONYM)— chebi
6β-(2,6-dimethoxybenzamido)penicillanic acid (EXACT_SYNONYM)— chebi
Methicillin (EXACT_SYNONYM)— chebi
Dimocillin (EXACT_SYNONYM)— aro
Metacillin (EXACT_SYNONYM)— aro
Methicillinum (EXACT_SYNONYM)— aro
Methycillin (EXACT_SYNONYM)— aro
Meticilina (EXACT_SYNONYM)— aro
Meticilline (EXACT_SYNONYM)— aro
Meticillinum (EXACT_SYNONYM)— aro
Staphcillin (EXACT_SYNONYM)— aro

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.

wikipedia.en:Meticillin

Activity roles

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

antimicrobial agent CHEBI:33281
antibacterial drug CHEBI:36047

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:0000015`	methicillin	`antibioticmech:aro-0633d1676e`	2026-08-30
CHEBI	`CHEBI:6827`	methicillin	`antibioticmech:chebi-fb6bb57072`	2026-08-30

Molecular targets

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

beta-lactam sensitive penicillin-binding protein PROTEIN DIRECT_BINDING_TARGET

ARO:3000749

CARD/ARO database assertion; target organism, strain, and assay are not specified. Penicillin-binding proteins are asserted as inhibited transpeptidases. Evidence status: PRIMARY_EVIDENCE_NEEDED. Source: CARD_ARO 2026-08-30 (retrieved 2026-08-30).

ARO:3000749 (CARD/ARO asserts targeted_by_antibiotic ARO:0000015 (methicillin); database assertion, not a primary citation.)

Resistance mechanisms

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

ANTIBIOTIC_TARGET_REPLACEMENT 4

ANTIBIOTIC_TARGET_REPLACEMENT
Determinant	ARO ID	Organism	Gene families	Evidence
mecA	ARO:3000617	not organism-specific	—	ARO:3000617 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000015 (methicillin); database assertion, not a primary citation.)
mecB	ARO:3003440	not organism-specific	—	ARO:3003440 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000015 (methicillin); database assertion, not a primary citation.)
mecC	ARO:3001209	not organism-specific	—	ARO:3001209 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000015 (methicillin); database assertion, not a primary citation.)
mecD	ARO:3004185	not organism-specific	—	ARO:3004185 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000015 (methicillin); database assertion, not a primary citation.)

ANTIBIOTIC_EFFLUX 1

ANTIBIOTIC_EFFLUX
Determinant	ARO ID	Organism	Gene families	Evidence
abcA	ARO:3003942	not organism-specific	—	ARO:3003942 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000015 (methicillin); database assertion, not a primary citation.)

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 2026-09-10 · seed_from_sources
Re-seeded from updated data/raw/ inventories

Provenance

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

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