1. A substance that renders another substance, or catalyst, active, or that accelerates a process or reaction. 2. The fragment, produced by chemical cleavage of a proactivator, that induces the enzymic activity of another substance. 3. An apparatus for making substances radioactive; e.g., neutron generator, cyclotron. 4. A removable type of myofunctional orthodontic appliance that acts as a passive transmitter of force, produced by the function of the activated muscles, to the teeth and alveolar process that are in contact with it.
catabolite gene a. (CGA) catabolite (gene) activator protein
plasminogen a. a proteinase converting plasminogen to plasmin by cleavage of a single (usually Arg-Val) bond in the former.urokinase;
polyclonal a. (pol-e-klo´nal) a substance that will activate T cells, B cells, or both regardless of their specificities.
tissue plasminogen a. (TPA) thrombolytic serine protease catalyzing the enzymatic conversion of plasminogen to plasmin through the hypolysis of a single Arg-Val bond; a genetically engineered protein used as a thrombolytic agent in patients with thrombotic occlusion of a coronary artery.
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