Induction of peptidylglycine alpha-amidating monooxygenase in N(18)TG(2) cells: A model for studying oleamide biosynthesis

The fatty-acid primary amide, oleamide, is a novel signaling molecule whose mechanism of biosynthesis is unknown. Recently, the N(18)TG(2) cell line w as shown to synthesize oleamide from oleic acid, thereby demonstrating that these cells contain the necessary catalytic activities for generating the fatty-acid primary amide. The ability of peptide alpha-amidating enzyme, pe ptidylglycine-alpha-amidating monooxygenase (PAM; EC 1.14.17.3), to catalyz e the formation of oleamide from oleoylglycine in vitro suggests this as a function for the enzyme in vivo. This investigation shows that N(18)TG(2) c ells, in fact, express PAM and that cellular differentiation dramatically i ncreases this expression PAM expression was confirmed by the detection of P AM mRNA, PAM protein, and enzymatic activity that exhibits the functional c haracteristics of PAM isolated from mammalian neuroendocrine tissues. The r egulated expression of PAM in N(18)TG(2) cells is consistent with the propo sed role of PAM in the biosynthesis of fatty-acid primary amides and furthe r establishes this cell line as a model for studying the pathway. (C) 2000 Academic Press.