an oxidized electron donor

a reduced electron donor

a deaminated amino group acceptor

an aminated amino group acceptor

Charged-LEU-tRNAs

LEU-tRNAs

a 2-oxo acid

an amino acid

an acyl-CoA

a carboxylate

an oxidized ferredoxin [iron-sulfur] cluster

a reduced ferredoxin [iron-sulfur] cluster

NAD(P)H

NAD(P)+

an L-tyrosyl-[tRNAtyr]

a tRNAtyr

(2Z,4Z)-2-hydroxy-5-carboxymuconate-6-semialdehyde

4α,14α-dimethyl-porifersta-8,25(27)-dienol

2-amino-4,5-dihydroxy-6-oxo-7-(phosphooxy)heptanoate

4-methylcyclohex-1,5-diene-1-carbonyl-CoA

isoshowacene

2-hydroxyhexadecanal

16-sinapoyloxypalmitate

3-methylquinolin-2-ol

(22R)-hydroxycholesterol

N-(2-methylpropyl)hydroxylamine

chloroeremomycin

3-hydroxy-3-methylbutanoate

2',3',4'-O-methyl-rhamnosyl tetracyclic spinosyn pseudoaglycone

2',3'-O-methyl-rhamnosyl tetracyclic spinosyn pseudoaglycone

2'-O-methyl-rhamnosyl tetracyclic spinosyn pseudoaglycone

rhamnosyl tetracyclic spinosyn pseudoaglycone

rhamnosyl tricyclic spinosyn pseudoaglycone

spinosyn tricyclic macrolactone

11-dehydro-15-oxo spinosyn macrolactone

15-oxo spinosyn macrolactone

spinosyn macrolactone

diethylamine N-oxide

triethylamine N-oxide

UDP-2-acetamido-2-deoxy-α-D-ribo-hex-3-uluronate

nitroxyl

trans,octacis-decaprenylphospho-β-D-arabinofuranose

1,3-dihydro-2H-imidazol-2-one

2-phenylethyl β-D-glucopyranoside

formyl hopane

ribosyl hopane

adenosyl hopane

(2Z)-2-hydroxypenta-2,4-dienoate

(2S,4S)-4-hydroxy-2,3,4,5-tetrahydrodipicolinate

(2Z)-2,4-dihydroxypent-2-enoate

(2E,7Z,10Z,13Z,16Z,19Z)-docosahexaenoyl-CoA

(3R,5Z,8Z,11Z,14Z,17Z)-3-hydroxydocosapentaenoyl-CoA

(5Z,8Z,11Z,14Z,17Z)-3-oxodocosapentaenoyl-CoA

(+)-3'-hydroxylarreatricin

(+)-larreatricin

2-trans,4-trans-xanthoxin

creatinine

pimelate

5-amino-1-(5-phospho-β-D-ribosyl)imidazole

L-arginino-succinate

pseudouridine

ammonia

(2S,4S)-2-methyl-2,4-dihydroxydihydrofuran-3-one

(2S,4S)-2-methyl-2,3,3,4-tetrahydroxytetrahydrofuran

H₂O

CO₂

3-amino-1-hydroxyacetone 1-phosphate

(2S)-2-amino-3-oxo-4-phosphooxybutanoate

4-phosphooxy-L-threonine

5-amino-6-(D-ribitylamino)uracil

3-deoxy-α-D-manno-2-octulosonate

3-deoxy-D-manno-octulosonate 8-phosphate

urea

L-canavanine

selenophosphate

5-amino-6-(5-phospho-D-ribosylamino)uracil

2,5-diamino-6-(5-phospho-D-ribosylamino)pyrimidin-4(3H)-one

4'-phosphopantetheine

(S)-3-methyl-2-oxopentanoate

3-methyl-2-oxobutanoate

4-methyl-2-oxopentanoate

hydrogen peroxide

pseudouridine 5'-phosphate

prenyl diphosphate

dethiobiotin

citrate

oxaloacetate

oxalosuccinate

7,8-diaminopelargonate

N-carbamoylputrescine

nicotinate adenine dinucleotide

β-nicotinate D-ribonucleotide

thiamine diphosphate

4-amino-2-methyl-5-(diphosphooxymethyl)pyrimidine

4-amino-2-methyl-5-(phosphooxymethyl)pyrimidine

thiamine phosphate

anthranilate

N-(5-phosphoribosyl)-anthranilate

orotidine 5'-phosphate

3-dehydroshikimate

shikimate

propionamide

4-guanidinobutanoate

4-guanidinobutyramide

(indol-3-yl)acetamide

acrylate

acrylamide

carbamoyl phosphate

coproporphyrinogen III

preuroporphyrinogen

isopentenyl diphosphate

N¹-(5-phospho-β-D-ribosyl)glycinamide

5-phospho-β-D-ribosylamine

O-acetyl-L-serine

carbonic acid

xanthine

L-arogenate

5'-phosphoribosyl-4-(N-succinocarboxamide)-5-aminoimidazole

indole-3-ethanol

D-gluconate 6-phosphate

6-phospho D-glucono-1,5-lactone

2-dehydro-3-deoxy-D-gluconate 6-phosphate

3-phosphooxypyruvate

(E)-4-hydroxy-3-methylbut-2-en-1-yl diphosphate

5-enolpyruvoyl-shikimate 3-phosphate

shikimate 3-phosphate

phosphoenolpyruvate

S-adenosyl-4-methylsulfanyl-2-oxobutanoate

8-amino-7-oxononanoate

glycerone phosphate

β-D-ribosylnicotinate

acetyl phosphate

(S)-dihydroorotate

pimeloyl-CoA

N-succinyl-2-amino-6-ketopimelate

N-succinyl-L,L-2,6-diaminopimelate

2-C-methyl-D-erythritol-2,4-cyclodiphosphate

H₂

N-methylhydantoin

acetoacetate

4-methyl-3-oxoadipate

α-D-glucosamine 1-phosphate

enol-phenylpyruvate

P¹,P⁴-bis(5'-guanosyl) tetraphosphate

N-acetyl-β-D-glucosamine-1,6-anhydro-N-acetyl-β-D-muramate

1-deoxy-L-glycero-tetrulose 4-phosphate

S-methyl-5'-thioadenosine

S-adenosyl 3-(methylsulfanyl)propylamine

(R)-4'-phosphopantothenoyl-L-cysteine

(R)-4'-phosphopantothenate

ADP-L-glycero-β-D-manno-heptose

ADP-D-glycero-β-D-manno-heptose

(R)-pantothenate

lipid A disaccharide (E. coli)

lipid X

3α,12α-dihydroxy-7-oxo-5β-cholan-24-oate

3-dehydroquinate

2-dehydropantoate

(S)-2-acetolactate

(S)-2-aceto-2-hydroxybutanoate

(R)-2,3-dihydroxy-3-methylpentanoate

lipid IV_A

5-aminolevulinate

(S)-4-amino-5-oxopentanoate

4-amino-4-deoxychorismate

prephenate

3-deoxy-D-arabino-heptulosonate 7-phosphate

porphobilinogen

glutathionylspermidine

2-C-methyl-D-erythritol 4-phosphate

hydrogen selenide

L-selenocystathionine

autoinducer 2

S-ribosyl-L-homocysteine

hydroxypyruvate

5-(methylsulfanyl)-α-D-ribose

quinolinate

DNA without lesion

glycolate

(3R)-3-hydroxy-2-oxo-4 phosphooxybutanoate

2-oxopent-4-enoate

(3E)-2-oxopent-3-enoate

(2E)-2-hydroxypenta-2,4-dienoate

(2Z,4E)-2-hydroxy-6-oxohexa-2,4-dienoate

(2E,4Z)-2-hydroxy-6-oxohepta-2,4-dienoate

D-glycero-β-D-manno-heptose 1-phosphate

D-glycero-β-D-manno-heptose 1,7-bisphosphate

pseudaminate

(3R,5S)-3-hydroxy-1-pyrroline-5-carboxylate

3-(O-geranylgeranyl)-sn-glycerol 1-phosphate

4-prenylphlorisobutyrophenone

norspermidine

carboxynorspermidine

carbon monoxide

2-(α-hydroxyethyl)thiamine diphosphate

core oligosaccharide-lipid A (E. coli K-12 core type)

propan-2-ol

2-amino-3-carboxymuconate-6-semialdehyde

N-acetyl-D-muramate 6-phosphate

1,6-anhydro-N-acetyl-β-muramate

(2R,4S)-2-methyl-2,3,3,4-tetrahydroxytetrahydrofuran

(2R,4S)-2-methyl-2,4-dihydroxydihydrofuran-3-one

2-iminoacetate

5-amino-6-(5-phospho-D-ribitylamino)uracil

7-epicholate

4-amino-2-methyl-5-pyrimidinemethanol

(2E,6E)-farnesyl diphosphate

riboflavin

thiamine

nicotinate

nicotinamide

5,6,7,8-tetrahydrofolate

tetrahydropteroyl tri-L-glutamate

5,10-methylenetetrahydropteroyl mono-L-glutamate

10-formyl-tetrahydrofolate mono-L-glutamate

5-methyltetrahydropteroyl mono-L-glutamate

5-methyltetrahydropteroyl tri-L-glutamate

(6S)-5-formyl-tetrahydrofolate mono-L-glutamate

7,8-dihydrofolate monoglutamate

N¹⁰-formyldihydrofolate

pyridoxine 5'-phosphate

pyridoxal 5'-phosphate

FAD

FMN

FMNH₂

NADH

NADPH

NAD⁺

NADP⁺

3-demethylubiquinol-8

menaquinol-8

ubiquinol-8

demethylmenaquinol-8

(S)-NADHX

(R)-NADHX

coenzyme A

acrylonitrile

(indole-3-yl)acetonitrile

preQ₀

2-octaprenylphenol

5,10-methenyltetrahydrofolate mono-L-glutamate

superoxide

CMP-N-acetyl-β-neuraminate

1-oleoyl-2-lyso-glycerone phosphate

(2R)-2,3-dihydroxy-3-methylbutanoate

3-phospho-D-glyceroyl-phosphate

(R)-glycerate

2,3-diphospho-D-glycerate

3-phospho-D-glycerate

2-phospho-D-glycerate

sn-glycerol 3-phosphate

sn-glycerol 1-phosphate

oxygen

hydrogen sulfide

protoporphyrinogen IX

uroporphyrinogen-III

protoporphyrin IX

coproporphyrinogen I

uroporphyrinogen-I

protoheme

DNA with lesion

L-cysteinylglycine

D-alanyl-D-alanine

L-alanyl-γ-D-glutamyl-meso-2,6-diaminopimeloyl-D-alanine

L-alanyl-γ-D-glutamyl-meso-diaminopimelate

2-iminopropanoate

2-iminosuccinate

2-iminobutanoate

hypoglycin B

D-methionine

D-alanine

D-glutamate

L-histidine

L-tryptophan

L-phenylalanine

L-tyrosine

L-cysteine

L-glutamine

L-asparagine

L-serine

glycine

L-threonine

L-arginine

L-lysine

L-glutamate

L-aspartate

L-leucine

L-alanine

L-proline

N-carbamoylsarcosine

β-alanine

L-citrulline

L-isoleucine

L-valine

L-methionine

L-cystine

L-4-hydroxyglutamate semialdehyde

S-adenosyl-L-homocysteine

S-adenosyl-L-methionine

L-ornithine

L-canaline

L-aspartate 4-semialdehyde

hypoglycin A

L-homoserine

O-phospho-L-homoserine

S-sulfo-L-cysteine

L-homocysteine

L-glutamate-5-semialdehyde

meso-diaminopimelate

L-selenocysteine

L-aspartyl-4-phosphate

L,L-diaminopimelate

L-cystathionine

N-carbamoyl-L-aspartate

L-saccharopine

seleno-L-homocysteine

sarcosine

3-phospho-L-serine

guanosine 2',3'-cyclic monophosphate

adenosine 2',3'-cyclic monophosphate

ADP

ATP

5'-deoxyadenosine

GDP

GTP

hypoxanthine

2'-deoxyinosine

5-chloro-5-deoxyribose 1-phosphate

5'-chloro-5'-deoxyadenosine

2'-deoxyadenosine

2'-deoxyguanosine

IMP

GMP

adenylo-succinate

dGDP

dADP

XMP

guanosine 3'-monophosphate

adenosine 3'-monophosphate

dGTP

ITP

IDP

dATP

dITP

dIDP

pppGpp

AMP

ppGpp

dGMP

dAMP

UDP-α-D-glucose

UDP-N-acetyl-α-D-muramoyl-L-alanyl-D-glutamate

UDP-α-D-galactose

UDP-N-acetyl-α-D-muramoyl-L-alanine

UDP-N-acetyl-α-D-muramate

UDP-N-acetyl-α-D-glucosamine-enolpyruvate

UDP-N-acetyl-α-D-muramoyl-L-alanyl-γ-D-glutamyl-L-lysine

UDP-2-N,3-O-bis[(3R)-3-hydroxytetradecanoyl]-α-D-glucosamine

UDP-3-O-[(3R)-3-hydroxymyristoyl]-N-acetyl-α-D-glucosamine

UDP-2-acetamido-2,6-dideoxy-β-L-arabino-hex-4-ulose

UDP-2-acetamido-2,6-dideoxy-α-D-xylo-hex-4-ulose

UDP-3-O-(3-hydroxymyristoyl)-α-D-glucosamine

UDP-2,4-diacetamido-2,4,6-trideoxy-β-L-altropyranose

UDP-4-amino-4,6-dideoxy-N-acetyl-β-L-altrosamine

UDP-N-acetyl-α-D-fucosamine

UDP-N-acetyl-α-D-quinovosamine

UDP-N-acetyl-α-D-muramoyl-L-alanyl-γ-D-glutamyl-meso-2,6-diaminopimeloyl-D-alanyl-D-alanine

UDP-N-acetyl-α-D-muramoyl-L-alanyl-γ-D-glutamyl-L-lysyl-D-alanyl-D-alanine

UDP-N-acetyl-α-D-muramoyl-L-alanyl-γ-D-glutamyl-meso-2,6-diaminopimelate

UDP-N-acetyl-α-D-muramoyl-L-alanyl-γ-D-glutamyl-L-lysyl-D-alanine

UDP-N-acetyl-α-D-glucosamine

GDP-4-dehydro-α-D-rhamnose

GDP-α-D-mannose

GDP-β-L-fucose

2-phospho-4-(cytidine 5'-diphospho)-2-C-methyl-D-erythritol

4-(cytidine 5'-diphospho)-2-C-methyl-D-erythritol

CMP-3-deoxy-β-D-manno-octulosonate

CMP-pseudaminate

inosine

xanthosine

guanosine

adenosine

cytidine

uridine

5'-deoxy-5'-fluoroadenosine

preQ₁

adenine

guanine

uracil

cytidine 2',3'-cyclic monophosphate

uridine 2'3'-cyclic monophosphate

dTDP

dUDP

dCDP

dUTP

dCTP

dTTP

dTMP

dUMP

dCMP

2-methylsulfanyl-N⁶-dimethylallyladenosine³⁷ in tRNA

2-sulfanyl-N⁶-dimethylallyladenosine³⁷ in tRNA

β-nicotinamide D-ribonucleotide

CMP

UMP

UDP

CDP

UTP

CTP

cytidine-3'-monophosphate

uridine 3'-monophosphate

(6R)-6-pyruvoyl-5,6,7,8-tetrahydropterin

6-(hydroxymethyl)-7,8-dihydropterin

7,8-dihydroneopterin

7,8-dihydromonapterin

(7,8-dihydropterin-6-yl)methyl diphosphate

7,8-dihydroneopterin 3'-triphosphate

7,8-dihydroneopterin 3'-phosphate

7,8-dihydropteroate

6,7-dimethyl-8-(1-D-ribityl)lumazine

reduced riboflavin

orotate

(S)-1-pyrroline-5-carboxylate

urate

4-methylphenol

4-aminobenzoate

indole

(indol-3-yl)acetaldehyde

(1S,2R)-1-C-(indol-3-yl)glycerol 3-phosphate

catechol

galactosyl-(glucosyl)₃-(heptosyl)₃-Kdo₂-lipid A-bisphosphate

galactosyl-(glucosyl)₂-(heptosyl)₃-Kdo₂-lipid A-bisphosphate

α-Kdo-(2→6)-lipid IV_A

heptosyl-Kdo₂-lipid IV_A

α-Kdo-(2->4)-α-Kdo-(2->6)-lipid IV_A

heptosyl-Kdo₂-lipid A

α-D-Kdo-(2→4)-α-D-Kdo-(2→6)-lipid A

(heptosyl)₂-Kdo₂-lipid A

glucosyl-(heptosyl)₂-Kdo₂-lipid A

glucosyl-(heptosyl)₂-Kdo₂-lipid A-phosphate

glucosyl-(heptosyl)₃-Kdo₂-lipid A-phosphate

glucosyl-(heptosyl)₃-Kdo₂-lipid A-bisphosphate

galactosyl-glucosyl-(heptosyl)₃-Kdo₂-lipid A-bisphosphate

di-trans,octa-cis-undecaprenyl phosphate

trans,octacis-decaprenyl phosphate

geranyl diphosphate

geranylgeranyl diphosphate

mono-trans,octa-cis-decaprenyl diphosphate

di-trans,octa-cis-undecaprenyl diphosphate

3-octaprenyl-4-hydroxybenzoate

(3S)-linalool

(3R)-linalool

1-linoleoyl-sn-glycero-3-phosphocholine

1-oleoyl-sn-glycerol 3-phosphate

1-oleoyl-2-palmitoyl-phosphatidylglycerol

dioleoyl phosphatidate

phosphatidylglycerophosphate (1-octadecenoyl(9Z), 2-palmitoyl)

1-palmitoyl-2-linoleoyl-phosphatidylcholine

phlorisovalerophenone

deoxycohumulone

deoxyhumulone

4-prenylphlorisovalerophenone

ferric-enterobactin complex

iron(III) dicitrate

3'-dephospho-CoA

acetyl-CoA

malonyl-CoA

(3R,11Z,14Z,17Z)-3-hydroxyicosatrienoyl-CoA

(11Z,14Z,17Z)-3-oxoicosatrienoyl-CoA

succinyl-CoA

2-methylacetoacetyl-CoA

(2S,3S)-3-hydroxy-2-methylbutanoyl-CoA

(E)-2-methylcrotonoyl-CoA

2-methylbutanoyl-CoA

oleoyl-CoA

propanoyl-CoA

butanoyl-CoA

(3R)-3-hydroxybutanoyl-CoA

3-oxoadipyl-CoA

4-methyl-3-oxoadipyl-CoA

acetoacetyl-CoA

3-oxopentanoyl-CoA

crotonyl-CoA

D-glucono-1,5-lactone

D-gluconate

1-(β-D ribofuranosyl)nicotinamide

maltotriose

maltotetraose

sucrose

glycolaldehyde

D-glyceraldehyde

aldehydo-D-ribose

β-D-ribofuranose

α-D-ribofuranose

β-D-glucopyranose

α-D-glucopyranose

β-D-fructofuranose

N-acetylmuramate

N-acetyl-α-D-muramoyl-L-alanine(1-)

N-acetyl-β-neuraminate

N-acetyl-α-D-glucosamine 1-phosphate

N-acetyl-β-D-glucosamine

2,4-diacetamido-2,4,6-trideoxy-β-L-altropyranose

decaprenyl-diphospho-N-acetylmuramoyl-pentapeptide

D-glyceraldehyde 3-phosphate

α-D-glucopyranose 1-phosphate

undecaprenyldiphospho-N-acetylmuramoyl-L-alanyl-γ-D-glutamyl-meso-2,6-diaminopimeloyl-D-alanyl-D-alanine

undecaprenyl-diphospho-N-acetylmuramoyl-L-alanyl-γ-D-glutamyl-L-lysyl- D-alanyl-D-alanine

a peptidoglycan dimer (mycobacteria)

a peptidoglycan dimer (E. faeciums)

a peptidoglycan dimer (E. faecium, tetrapeptide)

a peptidoglycan dimer (S. aureus)

decaprenyl-pyrophosphoryl-(N-acetylglucosamine)-N-acetylmuramyl-(pentapeptide)

undecaprenyl-diphospho-N-acetylmuramoyl-L-alanyl-γ-D-glutamyl-L-lysyl- D-alanine

a peptidoglycan dimer (meso-diaminopimelate containing)

a peptidoglycan with D,D cross-links (meso-diaminopimelate containing)

ditrans,octacis-undecaprenyldiphospho-[(N-acetyl-β-D-glucosaminyl)-(1,4)-]-N-acetyl-α-D-muramoyl-L-alanyl-γ-D-glutamyl-meso-2,6-diaminopimeloyl-D-alanyl-D-alanine

ditrans,octacis-undecaprenyldiphospho-N-acetyl-(N-acetylglucosaminyl)muramoyl-L-alanyl-γ-D-isoglutaminyl-N-(β-D-asparaginyl)-L-lysyl-D-alanyl-D-alanine

ditrans,octacis-undecaprenyldiphospho-N-acetyl-(N-acetylglucosaminyl)muramoyl-L-alanyl-γ-D-isoglutaminyl-N-(β-D-asparaginyl)-L-lysyl-D-alanine

ditrans,octacis-undecaprenyldiphospho-N-acetyl-(N-acetylglucosaminyl)muramoyl-L-alanyl-γ-D-isoglutaminyl-L-lysyl-(glycyl)₅-D-alanyl-D-alanine

ditrans,octacis-undecaprenyldiphospho-N-acetyl-(N-acetyl-β-D-glucosaminyl)muramoyl-L-alanyl-γ-D-glutamyl-L-lysyl-D-alanyl-D-alanine

ditrans,octacis-undecaprenyldiphospho-N-acetyl-(N-acetylglucosaminyl)muramoyl-L-alanyl-γ-D-glutamyl-L-lysyl-D-alanine

GlcNAc-1,6-anhMurNAc-L-Ala-γ-D-Glu-DAP-D-Ala

a peptidoglycan with L,D cross-links (mycobacteria)

a peptidoglycan with D,D cross-links (mycobacteria)

sucrose 6^F-phosphate

D-erythrose 4-phosphate

D-sedoheptulose 7-phosphate

5-phospho-α-D-ribose 1-diphosphate

1-(o-carboxyphenylamino)-1'-deoxyribulose 5'-phosphate

4-phospho-D-erythronate

D-fructose 6-phosphate

β-D-fructofuranose 6-phosphate

β-D-fructose 1,6-bisphosphate

α-D-glucose 6-phosphate

β-D-glucose 6-phosphate

β-D-mannopyranose 6-phosphate

α-D-mannopyranose 6-phosphate

1-deoxy-D-xylulose 5-phosphate

D-xylulose 5-phosphate

aldehydo-D-arabinose 5-phosphate

D-ribulose 5-phosphate

α-D-ribose-1-phosphate

5-fluoro-5-deoxy-D-ribose 1-phosphate

2-deoxy-α-D-ribose 1-phosphate

L-fuculose 1-phosphate

β-D-glucopyranose 1-phosphate

β-D-fructofuranose 1-phosphate

α-D-mannose 1-phosphate

diacetyl

acetone

(S)-lactaldehyde

acetaldehyde

formaldehyde

butan-1-al

palmitate

butanoate

pyruvate

2-oxoglutarate

2-oxobutanoate

glyoxylate

3-phenyl-2-oxopropanoate

3-(4-hydroxyphenyl)pyruvate

3-oxoadipate

acetate

formate

propanoate

(R)-lactate

(2R,3S)-2-methylisocitrate

chorismate

fumarate

succinate

(S)-malate

cis-2-methylaconitate

cis-aconitate

D-threo-isocitrate

(R)-pantoate

5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide

5-amino-4-imidazolecarboxyamide

acetamide

(indol-3-yl)acetate

3α,7α-dihydroxy-12-oxo-5β-cholan-24-oate

3α,7α,12β-trihydroxy-5β-cholan-24-oate

cholate

glycocholate

isocholate

3-dehydrocholate

ethylene glycol

ethanol

butan-1-ol

methanol

agmatine

spermidine

putrescine

2-aminoprop-2-enoate

(2Z)-2-aminobut-2-enoate

dimethyl sulfide

glutathione

3-sulfopyruvate

L-cysteate

4-methyl-5-(2-phosphooxyethyl)thiazole

2-[(2R,5Z)-2-carboxy-4-methylthiazol-5(2H)-ylidene]ethyl phosphate

2-(2-carboxy-4-methylthiazol-5-yl)ethyl phosphate

5-(2-hydroxyethyl)-4-methylthiazole

trimethyl sulfonium

selenide

thiosulfate

nitrite

nitrate

hydrogencarbonate

molybdate

phosphonate

phosphate

diphosphate

triphosphate

Fe³⁺

Ni²⁺

Cu²⁺

Cd²⁺

Fe²⁺

H⁺

ammonium