Felinine
From Wikipedia, the free encyclopedia
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| Names | |
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| IUPAC name
(2R)-2-Amino-3-[(3-hydroxy-1,1-dimethylpropyl)thio]propanoic acid | |
| Identifiers | |
3D model (JSmol) |
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| 2250979 | |
| ChEBI | |
| ChemSpider | |
PubChem CID |
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| UNII | |
CompTox Dashboard (EPA) |
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| Properties | |
| C8H17NO3S | |
| Molar mass | 207.29 g/mol |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Felinine, also known as (R)-2-amino-3-(4-hydroxy-2-methylbutan-2-ylthio)propanoic acid, is an amino acid found in cat urine and a precursor via microbial lyase of the putative cat pheromone and thiol called 3-mercapto-3-methylbutan-1-ol (MMB).[1] [2][3] Felinine is excreted by some Felidae species, including bobcats, Chinese desert cats, the kodkod, and domestic cats.
Felinine synthesis starts in the liver through a condensation reaction of glutathione and isopentenyl pyrophosphate to form 3-methylbutanolglutathionine (3-MBG).[4] Then, kidney epithelia tissue secretes γ-glutamyl transpeptidase (γ-GTP). γ-GTP converts 3-MBG to 3-methylbutanol-cysteinylglycine (MBCG). Next, a majority of MBCG is hydrolyzed to felinine and glycine by carboxylesterase 5A, or cauxin.[5] Cauxin specifically works by hydrolyzing the dipeptide (felinylglycine) in MBCG to increase the concentration of urinary felinine.[6] The leftover MBCG is converted to felinine and secreted into the cells where it is acetylated and transported to fecal material. Therefore, high concentration of felinine is present in urine while a minor concentration of N-acetylfelinine is present in cat excrement.[5]
- Glutathione + Isopentenyl Pyrophosphate → 3-MBG
- 3-MBG + γ-GTP → MBCG
- MBCG + Cauxin → Felinine + Glycine, or
- MBCG → N-Acetylfelinine
Urine of domestic cats may contain a series of felinine-containing compounds including free felinine, acetylfelinine, felinylglycine and 3-MBG.[7]
Cysteine also plays a role in the synthesis of felinine. For one, the amino acid is commonly present in many enzymes. Also, it is one of the few precursors for glutathione. Glutathione is converted to 3-MBG, and so cysteine has an important role in the early steps of synthesis.[8]
- Cysteine + Glycine + Glutamate → Glutathione
Uses
A precursor for mercaptan is 3-mercapto-3-methylbutanol (MMB). MMB is a chemical which gives a strong odor to cat urine. This smell is likely used for communicating amongst cats as well as scaring away predators and rivals. That is, the smell can mark their territory amongst other male cats and attract a female mate.[9]