Human erythrocyte acetylcholinesterase purification, properties and kinetic behavior.

摘要: Abstract 1. 1.|Human erythrocyte acetylcholine hydrolase (EC 3.1.1.7) is purified 2537-fold, by isolating membrane fragments, Triton X-100 extraction of the enzyme from membranes and DEAE-cellulose calcium phosphate gel chromatographies. 2. 2.|The a glycoprotein; it moves as single band in acrylamide electrophoresis. Electron microscopy, filtration density-gradient centrifugation indicate to be macromolecule, composed small spherical units. The easily forms reversible aggregates presence other proteins ( e.g. bovine serum albumin) preserve enzyme, catalytically active polymer. 3. 3.|The molecular characteristics, substrate specificity, influence pH temperature on hydrolysis, kinetic constants are different cholinesterases implicated receptor function. 4. 4.|The characteristics suggest that possesses allosteric behavior. polar substrate, acetylthiocholine, activates enzyme; specifically low binding constant for binding, outside center, calculated. Other quarternary nitrogen carrying compounds mytelase) also found either activate or inhibit compete with depending upon concentration hence activation enzyme. behavior depends temperature, highly ordered catalysis can only observed above 32 °C; this result may explained 5. 5.|Specific anionic activators such HCO 3 − , cis -oxaloacetate fructose 1,6-diphosphate established. Oxaloacetate specific; compound, similar mytelase, better activator activated