User:MarDel1234/Felinine

Biosynthesis
First, kidney epithelia tissue secretes γ-glutamyl transpeptidase (γ-GTP). γ-GTP is an enzyme used to convert 3-MBG to 3-methylbutanol-cysteinylglycine (MBCG). A majority of MBCG is hydrolyzed to felinine and glycine by carboxylesterase 5A, or cauxin. 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.


 * 1) Glutathione + Isopentenyl Pyrophosphate → 3-MBG
 * 2) 3-MBG + γ-GTP → MBCG
 * 3) * MBCG + Cauxin → Felinine, or
 * 4) * MBCG → N-Acetylfelinine

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.


 * 1) 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.

Felinine Variables
Felinine excretion is regulated by levels of testosterone, and so its concentration is dependent on the sex and age of the cat. For instance, cats with high levels of testosterone produce higher levels of 3-MBG. Consequently, non neutered males have significantly higher concentrations of felinine in their urine than females and neutered males. Furthermore, cauxin is a carboxylesterase enzyme which hydrolyzes 3-methylbutanol-cysteinylglycine (MBCG) into felinine. Thus, felinine is dependent upon cauxin, and cauxin is excreted most in male cats above the age of three months. Therefore, older cats, compared to young kittens, have higher concentrations of felinine.

Also, long hair cats have less cysteine to go around as the amino acid is also used for protein structures found in hair. Thus, long haired cats make less felinine than short haired cats.