CMBL is a cysteine hydrolase whose endogenous substrates and physiological function remain unknown. The protein catalyzes hydrolytic activation of ester-based prodrugs by cleaving dioxolone rings, converting prodrugs into their active metabolites. CMBL activates the angiotensin receptor blockers Olmesartan medoxomil and Azilsartan medoxomil into Olmesartan and Azilsartan, respectively, and can also activate beta-lactam antibiotics including Faropenem medoxomil and Lenampicillin. The gene is annotated to xenobiotic metabolic processes and localizes to the cytosol and extracellular exosomes. While CMBL's role in drug metabolism is well-characterized, its endogenous physiological function and substrate specificity beyond prodrug activation remain to be elucidated. Clinical associations include diverse conditions such as Barrett's esophagus, colorectal carcinoma, and chr5 pain, though the mechanistic link between CMBL variants and these phenotypes is not established from available literature.