Fatty Acid Amide Hydrolase (FAAH)
Genes from all 3 organisms encode predicted 579-amino acid proteins that each contain a putative transmembrane domain, an amidase consensus sequence, and a putative SH3-binding motif. The sequence of the human protein is 82% and 84% identical to those of rat and mouse FAAH
, respectively. Mammalian cells expressing rat or human FAAH exhibited high levels of oleamide hydrolase activity. Western blotting and cell fractionation studies indicated that this activity was associated with a 60 to 65 kD membrane protein. Human and rat FAAHs hydrolyzed a similar variety of fatty acid amides, although the human enzyme was quantitatively somewhat less selective. Northern blot analysis revealed that human FAAH is expressed as a 2.1-kb mRNA in various tissues, but not in heart or lung.