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.

CHEBI:17334 CHEBI:17334
CHEBI:88187 CHEBI:88187
ARO:3000008 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

Equivalent identifiers for this same structure in other resources.

ARO:0000015
cas:61-32-5
drugbank:DB01603
drugcentral:1744
kegg.compound:C07177
reaxys:966227
wikipedia.en:Meticillin
chembl:CHEMBL575
pubchem.compound:6087

Activity roles

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

CHEBI:33281 CHEBI:33281
CHEBI:36047 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 known routes by which microbes resist this compound, grounded in ARO where CARD models them. Grouped by mechanism type — expand a group to see its determinants.

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

Provenance

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