Anandamide amidohydrolase from porcine brain. Partial purification and characterization.

Abstract

Ethanolamide of arachidonic acid was isolated from porcine brain as an endogenous ligand for cannabinoid receptors, and referred to as anandamide.1 In consideration of various biological activities of anandamide,2 it is very important to elucidate how the production and degradation of this new compound are regulated by enzymes within the cells. The enzyme activity hydrolyzing anandamide to free arachidonic acid and ethanolamine has been considered physiologically important since anandamide loses its biological activity at this step (Fig. 1). Several research groups have reported the anandamide hydrolase activity in the particulate fractions of the brain and other tissues of various animal species.3–5 The specific enzyme activity in these crude preparations was in a range from 0.3 to 9 nmol/min/mg protein. It has also been reported that anandamide is synthesized by the enzymatic condensation of arachidonic acid and ethanolamine. The anandamide synthase activity was found in the brain with a specific activity of 2–3 nmol/min/mg protein.5,6,7 As reported recently, we found both the hydrolase and synthase activities in the microsome fraction of porcine brain,8 from which anandamide was first isolated by Devane and others.1 In this paper we will discuss the partially purified anandamide hydrolase of porcine brain with special reference to its identity with anandamide synthase. We will also describe the inactivation of anandamide by the catalysis of lipoxygenase enzymes.9