Anandamide amidohydrolase activity, released in the medium by Tetrahymena pyriformis. Identification and partial characterization

• Published in: FEBS letters Vol. 508; no. 3; pp. 327 - 331
• Main Authors: Karava, Vivi, Fasia, Lambrini, Siafaka-Kapadai, Athanassia
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 23.11.2001
• Subjects: Amidohydrolases - antagonists & inhibitors; Amidohydrolases - metabolism; Anandamide metabolism; Animals; Arachidonic Acid - metabolism; Arachidonic Acids - metabolism; Calcium - metabolism; Culture Media; Dithionitrobenzoic Acid - pharmacology; Dithiothreitol - pharmacology; Edetic Acid - pharmacology; Egtazic Acid - pharmacology; Endocannabinoids; Enzyme Inhibitors - pharmacology; Fatty acid amidohydrolase; Hydrogen-Ion Concentration; Hydrolysis; Lipid Metabolism; Magnesium - metabolism; Magnesium - pharmacology; Phenylmethylsulfonyl Fluoride - pharmacology; Phospholipids - metabolism; Polyunsaturated Alkamides; Secreted enzyme; Temperature; Tetrahymena pyriformis; Tetrahymena pyriformis - enzymology; Fatty acid amidohydrolase; Secreted enzyme; Anandamide metabolism; Tetrahymena pyriformis
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/S0014-5793(01)03095-2

Anandamide, an endogenous cannabinoid receptor ligand, was rapidly metabolized by Tetrahymena pyriformis in vivo. Metabolic products were mainly phospholipids as well as neutral lipids, including small amounts of free arachidonic acid. Anandamide amidohydrolase activity was detected in the culture medium by the release of [ 3H]arachidonic acid from [ 3H]anandamide, in a time- and concentration-dependent manner. Kinetic experiments demonstrated that the released enzyme had an apparent K m of 3.7 μM and V max 278 pmol/min/mg protein. Amidohydrolase activity was maximal at pH 9–10, was abolished by phenylmethylsulfonyl fluoride and was Ca 2+- and Mg 2+-independent. Thus, T. pyriformis is capable of hydrolyzing anandamide in vivo and releasing amidohydrolase activity.