Stabilization of fly head cholinesterase immobilized on a gelatin membrane

Immobilization of meat fly head cholinesterase in gelatin membrane essentially increases the enzyme stability and changes its kinetic characteristics: the Michaelis constant and maximum velocity of acetylthiocholine hydrolysis and also biomolecular velocity constant of phosphorylation by DDVP.     

Reactivation of phosphorylated cholinesterase immobilized in a gelatin membrane

The soluble and immobilized cholinesterases (acetyl cholinesterase of human blood erythrocytes (EC 3.1.1.7) and butyryl cholinesterase of equine blood serum, (EC 3.1.1.8] were inactivated by such irreversible inhibitors as diisopropyl fluorophosphate (DFP), O,O-dimethyl-O-(2,2)-dichlorovinyl) phosphate (DDVP), paraoxone, armine. The inactivated enzymes were reactivated under the effect of TMB-4 (1,1'-trimethylene-bis)-4-formyl-pyridine bromide (dioxime). The values of the reactivation rate constants proved to be equal both for the soluble and immobilized cholinesterases inactivated by the same irreversible inhibitor. The immobilized enzyme is simpler and more correct to study the reactivating action than the soluble one.     

Effect of low-intensity laser radiation on the brain cholinesterase activity of rats

In studying the activity of cholinesterase in subcellular fractions of rat brain affected by laser radiation of low intensity (9 mW) symbasic changes were noted which were more pronounced in vitro than in vivo.     

Effect of preganglionic sympathectomy on the cholinesterase activity in the superior cervical ganglia of rats and hamsters

Summary By employing biochemical assay and histochemical enzyme techniques the effect of preganglionic sympathectomy on the cholinesterase (ChE) activity in the superior cervical ganglia of rats and hamsters was investigated. Biochemical assays indicate that the ChE activity in the superior cervical ganglia of adult rats and hamsters is 57.19 and 28.63 respectively (expressed in u moles acetylcholine hydrolyzed per min per g of tissue); two weeks after preganglionic denervation, about 50% and 60% of ChE activity are lost respectively. Histochemical enzyme examination reveals that in the rat superior cervical ganglion, the majority of the neurons are adrenergic with weak to moderate acetylcholinesterase (AChE) reaction and the minority of the neurons are cholinergic with strong AChE activity, while only one type of adrenergic neurons exhibits a weak AChE activity in the hamster superior cervical ganglion. The AChE activity is localized in the perinuclear area, in the cisternae of the rough surfaced endoplasmic reticulum, in the Golgi complex and on the plasma membrane of the hamster's neurons; it is mainly localized in the cisternae of the rough surfaced endoplasmic reticulum of the rat's neurons. AChE reaction product is also detected on the axolemmal membranes of the preganglionic nerve fibers in the sympathetic ganglia of rats and hamsters.After preganglionic sympathectomy, the AChE activity in the adrenergic neurons and in the preganglionic unmyelinated nerve fibers is markedly reduced, whereas the cholinergic neurons and preganglionic myelinated nerve fibers remain unchanged. On the basis of these results two conclusions have been reached: (1) The fact that strong AChE activity localized in the cholinergic neurons and preganglionic myelinated fibers is not influenced by denervation, suggests that these structures are able to produce AChE. (2) The reduction of AChE activity in the rat and hamster superior cervical ganglia two weeks after preganglionic denervation, observed by histochemical examination, can be correlated with a concomitant measurable reduction determined by biochemical assays.Supported in part by a grant from the National Science Council, Republic of China. The author wishes to express his gratitude to the Department of Pharmacology, College of Medicine, National Taiwan University, for the use of its equipment for biochemical assays