A neutral compound having formal unit electrical charges of opposite sign on non-adjacent atoms. Sometimes referred to as inner salts, dipolar ions (a misnomer).
| Member | Definition | Role |
|---|
| 1-methylhistidine | | N(tele)-methyl-L-histidine zwitterion; N(tele)-methyl-L-histidine |
| 2-(n-morpholino)ethanesulfonic acid | A Good's buffer substance, pKa = 6.15 at 20 degreeC. | 2-(N-morpholiniumyl)ethanesulfonate; 2-(N-morpholino)ethanesulfonic acid |
| 2-ketoarginine | Zwitterionic form of 5-guanidino-2-oxopentanoic acid. | 5-guanidino-2-oxopentanoic acid zwitterion; 5-guanidino-2-oxopentanoic acid |
| 3-aminopropylphosphonic acid | A zwitterion resulting from the transfer of a proton from the phosphonic acid group to the amino group of (3-aminopropyl)phosphonic acid; the major species at pH 7.3. | (3-aminopropyl)phosphonic acid zwitterion; (3-aminopropyl)phosphonic acid |
| 3-methylhistidine | | N(pros)-methyl-L-histidine zwitterion; N(pros)-methyl-L-histidine |
| 3,4-dihydro-2h-pyrrole-5-carboxylic acid | A zwitterion resulting from the transfer of a proton from the carboxy group to the nitrogen of 1-pyrroline-2-carboxylic acid; major species at pH 7.3. | 1-pyrroline-2-carboxylic acid zwitterion; 1-pyrroline-2-carboxylic acid |
| aclacinomycin | A zwitterion obtained by transfer of a proton from the 5-hydroxy to the tertiary amino group of aclacinomycin T. It is the major microspecies at pH 7.3 (according to Marvin v 6.2.0.). | aclacinomycin T zwitterion; aclacinomycin T |
| aclarubicin | A zwitterion obtained by transfer of a proton from the 5-hydroxy to the tertiary amino group of aclacinomycin A. It is the major microspecies at pH 7.3 (according to Marvin v 6.2.0.). | aclacinomycin A zwitterion; aclacinomycin A |
| alanyllactate | A zwitterion obtained by transfer of a proton from the carboxylic acid group to the amino group of D-alanyl-(R)-lactic acid. The major species at pH 7.3. | D-alanyl-(R)-lactic acid zwitterion; D-alanyl-(R)-lactic acid |
| alpha-keto-delta-guanidinovaleric acid | Zwitterionic form of 5-guanidino-2-oxopentanoic acid. | 5-guanidino-2-oxopentanoic acid zwitterion; 5-guanidino-2-oxopentanoic acid |
| aminoethylphosphonic acid | Zwitterionic form of (2-aminoethyl)phosphonic acid. | (2-aminoethyl)phosphonic acid zwitterion; (2-aminoethyl)phosphonic acid |
| anserine | Zwitterionic form of anserine. | anserine zwitterion; anserine |
| aszonalenin | | (2R,3S,11R)-aszonalenin zwitterion |
| baci-im | | bacitracin A zwitterion; bacitracin A |
| boromycin | A boron-containing macrolide antibiotic that is isolated from Streptomyces antibioticus. | boromycin |
| ciprofloxacin | A zwitterion formed from ciprofloxacin by transfer of a proton from the carboxy to the amino group; major species at pH 7.3. | ciprofloxacin zwitterion; ciprofloxacin |
| creatine | Zwitterionic form of creatine arising from transfer of a proton from the carboxy to the guanidino group; major species at pH 7.3. | creatine zwitterion; creatine |
| cycloserine | A zwitterion resulting from the transfer of a proton from the ring nitrogen to the primary amino group of D-cycloserine. The major species at pH 7.3. | D-cycloserine zwitterion; D-cycloserine |
| cysteinyldopa | | 5-S-cysteinyldopa zwitterion; Cysteinyldopa |
| delta(1)-piperidine-2-carboxylic acid | A zwitterion resulting from the transfer of a proton from the carboxy group to the nitrogen of 1-piperideine-2-carboxylic acid | 1-piperideine-2-carboxylic acid zwitterion; 1-piperideine-2-carboxylic acid |
| dopamine 3-o-sulfate | A zwitterion obtained by transfer of a proton from the sulfonyl to the amino group of dopamine 3-O-sulfate; major species at pH 7.3. | dopamine 3-O-sulfate zwitterion; dopamine 3-O-sulfate |
| dopamine 4-o-sulfate | A zwitterion obtained by transfer of a proton from the sulfonyl to the amino group of dopamine 4-O-sulfate; major species at pH 7.3. | dopamine 4-O-sulfate zwitterion; dopamine 4-O-sulfate |
| e 64 | | E64 zwitterion; E64 |
| ectoine | A zwitterion obtained by transfer of a proton from the carboxy group to the nitrogen alpha to the carboxy group. The major species at pH 7.3. | ectoine zwitterion; ectoine |
| gamma-guanidinobutyric acid | Zwitterionic form of 4-guanidinobutanoic acid. | 4-guanidinobutanoic acid zwitterion; 4-guanidinobutanoic acid; 4-guanidinobutyric acid |
| glycocyamine | Zwitterionic form of guanidinoacetic acid having an anionic carboxy group and a protonated guanidino group; major species at pH 7.3. | guanidinoacetic acid zwitterion; guanidinoacetic acid |
| guanidinoethane sulfonate | Zwitterionic form of taurocyamine arising from transfer of a proton from the sulfo to the guanidino group; major species at pH 7.3. | taurocyamine zwitterion; taurocyamine |
| guanidinopropionic acid | Zwitterionic form of 3-guanidinopropanoic acid having an anionic carboxy group and a protonated imine nitrogen. | 3-guanidinopropanoic acid zwitterion; 3-guanidinopropanoic acid |
| hypotaurine | Zwitterionic form of hypotaurine arising from migration of a proton from the sulfonate group to the amino group; major species at pH 7.3. | hypotaurine zwitterion; hypotaurine |
| iminoglycine | A zwitterion obtained by transfer of a proton from the carboxy to the imino group of dehydroglycine. It is the major microspecies at pH 7.3 (according to Marvin v 6.2.0.). | dehydroglycine zwitterion; dehydroglycine |
| imipenem, anhydrous | Zwitterionic form of imipenem having an anionic carboxy group and a protonated methaneimidamido group; major species at pH 7.3. | imipenem zwitterion; imipenem |
| ly 163892 | The zwitterionic form of loracarbef. | loracarbef zwitterion; loracarbef |
| molsidomine | A member of the class of oxadiazoles that is 1,2,3-oxadiazole substituted by morpholin-4-yl and (ethoxycarbonyl)azanidyl groups at positions 3 and 5, respectively. It is used as a vasodilator drug for the treatment of myocardial ischemic syndrome and congestive heart failure. | 1-ethoxy-N-[3-(4-morpholinyl)-5-oxadiazol-3-iumyl]methanimidate; molsidomine |
| molsidomine | A member of the class of oxadiazoles that is 1,2,3-oxadiazole substituted by morpholin-4-yl and (ethoxycarbonyl)azanidyl groups at positions 3 and 5, respectively. It is used as a vasodilator drug for the treatment of myocardial ischemic syndrome and congestive heart failure. | 1-ethoxy-N-[3-(4-morpholinyl)-5-oxadiazol-3-iumyl]methanimidate; molsidomine |
| muraymycin d2 | | muraymycin D2 zwitterion |
| phaclofen | | phaclofen zwitterion |
| rifampin | A zwitterion obtained by transfer of a proton from the 5-hydroxy group to the tertiary amino group of rifampicin. | rifampicin zwitterion; rifampicin |
| s-methyl glutathione | A zwitterion resulting from the transfer of a proton for the carboxy group to the amino group of the L-gamma-glutamyl residue of S-methylglutathione. | S-methylglutathione zwitterion; S-methylglutathione |
| serpentine (alkaloid) | An indole alkaloid that is 18-oxayohimban dehydrogenated at positions 3, 4, 5, 6, 16 and 17 and substituted by a methyl group at the 19alpha position and by a methoxycarbonyl group at position 16. | serpentine |
| taurine | The zwitterion formed from taurine by transfer of a proton from the sulfonyl to the amino group. It is the major species existing at physiological pH. | taurine zwitterion; taurine |
| tramiprosate | Zwitterionic form of 3-aminopropanesulfonic acid arising from transfer of a proton from the sulfo to the amino group; major species at pH 7.3. | 3-aminopropanesulfonic acid zwitterion; 3-aminopropanesulfonic acid |
| tyramine o-sulfate | A zwitterion obtained by transfer of a proton from the sulfate to the amino group of tyramine sulfate; major species at pH 7.3. | sulfuric acid [4-(2-aminoethyl)phenyl] ester; tyramine sulfate zwitterion; tyramine sulfate |