Application Methods: Immunohistochemistry (Paraffin), Immunoprecipitation, Western Blotting
Background: Catechol-O-methyltransferase (COMT) is an intracellular enzyme that catalyzes the O-methylation and inactivation of catecholamine neurotransmitters and hormones, including dopamine, epinephrine, and norepinephrine (1). Two distinct COMT proteins are generated from separate promoters in cells, including a 28 kDa, membrane-bound protein (mb-COMT), and a soluble protein (s-COMT) of 24 kDa (2,3). The soluble s-COMT is the predominant form of COMT found in peripheral organs, while the mb-COMT protein is more abundant in the central nervous system (4,5).In addition to inactivating endogenous catecholamines, COMT can also inhibit catechol-based drugs used to treat a number of disorders, including Parkinson's disease and schizophrenia. Research studies using COMT inhibitors indicate that these reagents can prolong the bioavailability of psychoactive drugs such as levodopa by preventing O-methylation and subsequent degradation (6). A Val158Met polymorphism in the corresponding COMT gene reduces COMT enzymatic activity and leads to increased cortical dopamine levels (7). Several research studies suggest that this reduced COMT activity is associated with a large number of mental disorders, including schizophrenia, bipolar disorder, attention deficit hyperactivity disorder, obsessive-compulsive disorder, and anorexia nervosa (reviewed in 8).
Application Methods: Immunohistochemistry (Paraffin), Western Blotting
Background: Ectonucleoside triphosphate diphosphohydrolase 1 (NTPDase 1, also known as CD39) is a multi-pass membrane ectoenzyme that metabolizes adenosine tri-phosphate (ATP) to regulate purinergic signaling. Purinergic signaling by extracellular ATP and its metabolites regulate many biological processes, including vascular tone, digestion, neuronal function, and inflammation in both normal and diseased states (1). NTPDase 1 is expressed in endothelial cells in the vasculature to regulate local platelet purinergic signaling via metabolism of ATP to adenosine (2). Accordingly, NTPDase 1 regulates platelet activation aggregation and contributes to the antithrombotic properties of endothelial cells (3). ATP and its metabolites also finely modulate the activity of T cells and macrophages (4, 5). Immunomodulation is regulated, in part, by the availability of extracellular ATP and adenosine, suggesting that NTPdase 1 (CD39) may play an immunosuppressive role in the tumor microenvironment.