Vertebrate Cholinesterases: Structure and Types of Interaction

Cholinesterases (ChEs) hydrolyse choline esters specifically and rapidly and thus play an essential role in cholinergic transmission, e. g. at the neuromuscular junctions of vertebrates. Vertebrates possess two distinct ChEs, acetylcholinesterase (AChE, EC 3.1.1.7) and butyrylcholinesterase, also called pseudocholinesterase or non-specific cholinesterase (BuChE, EC 3.1.1.8). Both these enzymes present multiple molecular variants which possess identical catalytic activity but differ in their molecular structure and interactions. The molecular variants can be differentiated by various analytical procedures. We find it useful first to classify them as molecular forms, according to their hydrodynamic parameters (sedimentation coefficient, Stokes radius), corresponding to different quaternary structures.