Glossary
Felinine — Glossary
A cat-specific amino acid in urine that degrades into sulfur odorants — the reason cat urine smells worse with age.
Felinine is a sulfur-containing amino acid found almost only in cat urine — highest in intact males. It degrades slowly into MMB, the mercaptan-class molecule behind the sharp tomcat smell.
It is a time-release odor capsule: mild at deposit, worse days later as the conversion continues. Residual felinine keeps producing until it is removed.