Classification and Comparative Enzymology of the Cholinesterases and Methods for their Determination

Augustinsson, Klas‐Bertil

doi:10.1007/978-3-642-99875-1_4

Cited by 81 publications

(20 citation statements)

References 200 publications

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“…Values for the Km of butyrylcholine ranged from 0.56 mm with cat plasma to 1 mm with dog plasma. The values obtained for human plasma with usual or atypical cholinesterase were similar to those reported by Davies, Marton & Kalow (1960), but in general all values were slightly lower than those reported by Augustinsson (1963). Differences in the ionic composition of the medium probably account for this (Myers, 1952).…”

Section: Discussionsupporting

confidence: 66%

Hydrolysis of suxamethonium by different types of plasma

Hobbiger

Peck

1969

British J Pharmacology

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1. A method, based on the use of the isolated frog rectus aibdominis preparation, is described for studying quantitatively the hydrolysis of suxamethonium at low concentrations. 2. Rates of hydrolysis of butyrylcholine, 10 mm, benzoylcholine, 0.05 mm, and suxamethonium, 0025 mM, by plasma from different species and human plasma with genetic variants of cholinesterase were measured. 3. The rates of hydrolysis of suxamethonium by different types of plasma vary widely. Human plasma with usual cholinesterase and monkey plasma hydrolyse suxamethonium more speedily than do the plasma of cats, dogs and rats, and human plasma with either atypical or fluoride resistant cholinesterase. This is only to a small extent attril'butable to differences in enzyme concentration and not explained by the presence of an inhibitor. 4. The Km values for butyrylcholine are very similar for different types of plasma but the K, values for suxamethonium in the system plasma-butyrylcholine-suxamethonium vary greatly. 5. These results and observations on the inhibition by decamethonium of the hydrolysis of butyrylcholine are consistent with the interpretation that the rates of hydrolysis of suxamethonium, 0.025 mm, obtained with different types of plasma vary because they are a function of two variables, the affinity of the ester for cholinesterase and the stability of the monosuccinyl derivative of the cholinesterase. It seems that human plasma with atypical cholinesterase hydrolyses suxamethonium much slower than does human plasma with usual cholinesterase mainly or solely because of differences in affinity of the ester for the two enzymes. On the other hand, cat plasma appears to hydrolyse suxamethonium much slower than does human plasma with usual cholinesterase mainly because the monosuccinyl derivative of cholinesterase in cat plasma is much more stable than that in human plasma. The reverse might apply for monkey plasma. 6. Inhibition by dibucaine or sodium fluoride of the hydrolysis of benzoylcholine is not a general guide to rates of hydrolysis of suxamethonium by different types of plasma.Suxamethonium (succinyldicholine; SDCh) is a neuromuscular blocking agent which is hydrolysed by acylcholine acyl-hydrolase (E.C.3.1.1.8; cholinesterase; butyrylcholinesterase) and thus has a brief duration of action. Enzymic hydrolysis

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Section: Discussionsupporting

confidence: 66%

Hydrolysis of suxamethonium by different types of plasma

Hobbiger

Peck

1969

British J Pharmacology

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“…Acetylcholinesterase is, for example, found in erythrocytes (Augustinsson, 1963), choline-acetyltransferase in the placenta (Whittaker, 1963), and nicotinic receptors at the tendon (Miledi et al, 1984). Unexpected localization of the release machinery itself has also been suspected from recent experiments showing that glial ,cells, fibroblasts, and other cell types, loaded in culture with acetylcholine (AcCh), were subsequently able to release the neurotransmitter, either in response to a calcium influx or after electrical stimulation Falk-Vairant et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

Cell lines expressing an acetylcholine release mechanism; correction of a release-deficient cell by mediatophore transfection

et al. 1996

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“…3 shows the gradient distribution of AChE, representing the specialized junctional area of the muscle membrane. DFP and eserine (physostigmine) were used to separate the specific junctional AChE from other esterases (20). All activity subsequent to "crude membranes" (Plo0H20) is due to cholinesterase, since eserine (10-5 M) completely inhibits.…”

Section: Resultsmentioning

confidence: 99%

In Vitro Analysis of the General Properties and Junctional Receptor Characteristics of Skeletal Muscle Membranes. Isolation, Purification, and Partial Characterization of Sarcolemmal Fragments

Festoff¹,

Engel²

1974

Proc. Natl. Acad. Sci. U.S.A.

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Muscle membranes were partially purified from rat leg muscles. Externally oriented membrane functions were used to monitor and characterize the resulting membrane fractions. Na+K+mstimulated Mg++-adenosinetriphosphatase, acetylcholinesterase, and cholinergic receptor activities are present and enriched in the density-gradient subfractions of crude sarcolemma when compared with the first pellet. The physical separation of the cholinesterase and receptor activities on the gradient subfractions is demonstrated.Receptor activity, determined by specific la6I-labeled alpha-bungarotoxin binding, appears in fractions with densities similar to other plasma membranes (D4 1.1015-1.1520). Acetylcholinesterase, on the other hand, is preferentially distributed in lighter density fractions (D4" 1.0507-1.0780) and parallels the gradient distribution of the ATPase. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis, a high-molecular-weight glycoprotein sediments with the higher density fractions only.The data suggest a molecular dissection of the layers of the sarcolemma. The receptor is tentatively felt to be an integral component of the junctional plasma membrane. Acetylcholinesterase is felt to be superficially located on the ectolamina of the junctional sarcolemma, and may be woven within the matrix of the intersynaptic basement membrane.Muscle membranes possess properties found in the membranes of all living cells as well as those unique to excitable tissues. Muscle, however, has not been extensively used as a model system for evaluatingnew concepts and methodology of membrane molecular biology. Its relative resistance to cell disruption, extensive connective tissue network, and the multiple layers of the sarcolemma may partially account for this. For the purposes of this paper, the sarcolemma is defined as a multilayered envelope covering the muscle cell, including, as its inner sheath, the trilaminar plasmalemma (true plasma membrane) external to which is a basement membrane, also composed of several layers. Attempts have been made to isolate "purified" skeletal muscle sarcolemma, with varying degrees of success (1-6). We have used a modification of a method used to prepare amphibian muscle membrane (3) for our work on a mammalian sarcolemma.

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Classification and Comparative Enzymology of the Cholinesterases and Methods for their Determination

Cited by 81 publications

References 200 publications

Hydrolysis of suxamethonium by different types of plasma

Hydrolysis of suxamethonium by different types of plasma

Cell lines expressing an acetylcholine release mechanism; correction of a release-deficient cell by mediatophore transfection

In Vitro Analysis of the General Properties and Junctional Receptor Characteristics of Skeletal Muscle Membranes. Isolation, Purification, and Partial Characterization of Sarcolemmal Fragments

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