ACTION OF ORGANOPHOSPHORUS COMPOUNDS UPON ESTERASES OF HUMAN LIVER

1963 ◽  
Vol 41 (7) ◽  
pp. 1537-1546 ◽  
Author(s):  
D. J. Ecobichon ◽  
W. Kalow
Keyword(s):  
Human Serum ◽  
Human Liver ◽  
Organophosphorus Compounds ◽  
Chemical Conversion ◽  
The Other ◽  
Serum Cholinesterase ◽  
Organophosphorus Insecticides ◽  
Low Concentrations ◽  
Starch Gel ◽  
Per Se

Human serum and liver esterases separated electrophoretically in starch gel were exposed to two series of organophosphorus insecticides. One series consisted of compounds active per se, the other of analogues requiring metabolic or chemical conversion to produce potent anticholinesterases. The results indicated that only one fraction of the liver, designated as zone L-2, is inhibited by low concentrations of all insecticides. This fraction shows a similar pattern of susceptibility to different inhibitors as does human serum cholinesterase. Of the other two zones of activity in liver, zone L-1 was found to be more susceptible to activated thionate, dithioate, and thioether derivatives than was zone L-3, while the latter zone was more susceptible to phosphates active per se.

ACTION OF ORGANOPHOSPHORUS COMPOUNDS UPON ESTERASES OF HUMAN LIVER

1963 ◽  
Vol 41 (1) ◽  
pp. 1537-1546 ◽  
Author(s):  
D. J. Ecobichon ◽  
W. Kalow
Keyword(s):  
Human Serum ◽  
Human Liver ◽  
Organophosphorus Compounds ◽  
Chemical Conversion ◽  
The Other ◽  
Serum Cholinesterase ◽  
Organophosphorus Insecticides ◽  
Low Concentrations ◽  
Starch Gel ◽  
Per Se

Human serum and liver esterases separated electrophoretically in starch gel were exposed to two series of organophosphorus insecticides. One series consisted of compounds active per se, the other of analogues requiring metabolic or chemical conversion to produce potent anticholinesterases. The results indicated that only one fraction of the liver, designated as zone L-2, is inhibited by low concentrations of all insecticides. This fraction shows a similar pattern of susceptibility to different inhibitors as does human serum cholinesterase. Of the other two zones of activity in liver, zone L-1 was found to be more susceptible to activated thionate, dithioate, and thioether derivatives than was zone L-3, while the latter zone was more susceptible to phosphates active per se.

Ultrasonic Effects on lsoenzymes

1966 ◽  
Vol 12 (4) ◽  
pp. 181-186 ◽  
Author(s):  
Clyde A Dubbs
Keyword(s):  
Human Serum ◽  
Ultrasonic Treatment ◽  
Gel Electrophoresis ◽  
Serum Proteins ◽  
Serum Cholinesterase ◽  
Starch Gel Electrophoresis ◽  
Selective Activation ◽  
Intracellular Enzymes ◽  
Starch Gel

Abstract Several significant effects of ultrasonic treatment on human serum cholinesterase and aminopeptidase isoenzymes and on other serum proteins have been found by starch gel electrophoresis. The selective activation of one cholinesterase isoenzyme is especially striking. These effects must be considered when ultrasonic treatment is used for the extraction of intracellular enzymes. When the effects are appreciated, ultrasonics should provide a valuable tool for isoenzyme research.

THE EFFECTS OF SIALIDASE ON PSEUDOCHOLINESTERASE TYPES

1963 ◽  
Vol 41 (1) ◽  
pp. 969-974 ◽  
Author(s):  
D. J. Ecobichon ◽  
W. Kalow
Keyword(s):  
Sialic Acid ◽  
Amino Acid ◽  
Human Serum ◽  
Acid Content ◽  
Protein Molecule ◽  
Serum Cholinesterase ◽  
Kinetic Properties ◽  
Sialic Acid Content ◽  
Starch Gel ◽  
A Charge

Hereditary variants of human serum cholinesterase were exposed to the action of sialidase. The removal of the sialic acid residues had no effect on the kinetic properties of the esterases but greatly affected the electrophoretic mobility. In starch gel, there were no differences between the pseudocholinesterase types whether sialidase-treated or untreated. This observation permits two conclusions: first, the differences between the esterase types must reside in the protein cores, and second, the different variants must possess equal amounts of sialic acid per protein molecule. According to Liddell et al. there is a charge difference between esterase molecules of different type; since this cannot be accounted for by sialic acid content, the distinguishing characteristics are likely due to differences of amino acid composition.

PROPERTIES AND CLASSIFICATION OF THE SOLUBLE ESTERASES OF HUMAN SKELETAL AND SMOOTH MUSCLE

1965 ◽  
Vol 43 (1) ◽  
pp. 73-79 ◽  
Author(s):  
D. J. Ecobichon ◽  
W. Kalow
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Human Liver ◽  
Renal Tissue ◽  
Water Soluble ◽  
Serum Cholinesterase ◽  
Liver And Kidney ◽  
Starch Gel ◽  
Zone Characteristic

Water-soluble proteins and enzymes of human skeletal and smooth muscle were separated by vertical-zone electrophoresis in starch gel and compared with those of human liver and kidney. Thirteen bands of proteins were detected with amido black in skeletal muscle, five of which were also detected in smooth muscle. Various substrates and inhibitors were used in efforts to identify enzymes. Ten bands of esterase activity were detected in skeletal muscle, and nine in smooth muscle. One zone, characteristic of serum cholinesterase, was believed to be due to serum contained in the tissue. A zone of isozymic esterases found in skeletal and smooth muscle was similar to a zone in human liver and kidney and reacted like an acetylesterase. Other esterase bands, which showed a marked hydrolysis of α-naphthyl butyrate, were similar to aliesterases of renal tissue. Observations on alkaline phosphatase, acid phosphatase, aminopeptidase, lactate dehydrogenase, and catalase were recorded for comparison with the data on esterases.

THE EFFECTS OF SIALIDASE ON PSEUDOCHOLINESTERASE TYPES

1963 ◽  
Vol 41 (4) ◽  
pp. 969-974 ◽  
Author(s):  
D. J. Ecobichon ◽  
W. Kalow
Keyword(s):  
Sialic Acid ◽  
Amino Acid ◽  
Human Serum ◽  
Acid Content ◽  
Protein Molecule ◽  
Serum Cholinesterase ◽  
Kinetic Properties ◽  
Sialic Acid Content ◽  
Starch Gel ◽  
A Charge

Hereditary variants of human serum cholinesterase were exposed to the action of sialidase. The removal of the sialic acid residues had no effect on the kinetic properties of the esterases but greatly affected the electrophoretic mobility. In starch gel, there were no differences between the pseudocholinesterase types whether sialidase-treated or untreated. This observation permits two conclusions: first, the differences between the esterase types must reside in the protein cores, and second, the different variants must possess equal amounts of sialic acid per protein molecule. According to Liddell et al. there is a charge difference between esterase molecules of different type; since this cannot be accounted for by sialic acid content, the distinguishing characteristics are likely due to differences of amino acid composition.

Fibrinolytic Activity of Thrombin Preparations

1964 ◽  
Vol 11 (01) ◽  
pp. 234-242 ◽  
Author(s):  
Pieter Brakman ◽  
Panpit Klug ◽  
Tage Astrup
Keyword(s):  
Protease Activity ◽  
Fibrinolytic Activity ◽  
The Other ◽  
Fibrinolytic Agents ◽  
Fibrinolytic Agent ◽  
Low Concentrations ◽  
Fibrin Plate ◽  
Simple Chemical ◽  
Per Se ◽  
High Concentrations

SummarySome thrombin samples have a slight unspecific protease activity probably caused by contaminating plasmin. All investigated samples were fibrinolytically active. This activity was caused by an activator of plasminogen. Fibrinolytic activity was apparently produced by two components of the thrombin preparations. One of these components was a contaminant with fibrinolytic activity but with no thrombin activity. This component could be separated from the thrombin by simple chemical procedures. The other fibrinolytic component appeared to be the thrombin molecule per se. It was not fibrinolytically active when used in the low concentrations required for clotting of fibrinogen, but in high concentrations, assayed on the fibrin plate, it activated plasminogen. In the accurate assay of fibrinolytic agents it is necessary to use preparations of thrombin from which the contaminating fibrinolytic agent has been removed.

SOME PROPERTIES OF THE SOLUBLE ESTERASES OF HUMAN LIVER

1961 ◽  
Vol 39 (9) ◽  
pp. 1329-1332 ◽  
Author(s):  
D. J. Ecobichon ◽  
W. Kalow
Keyword(s):  
Human Serum ◽  
Human Liver ◽  
Histochemical Staining ◽  
Enzymatic Properties ◽  
Water Soluble ◽  
Electrophoretic Migration ◽  
Zone Electrophoresis ◽  
Starch Gel ◽  
Staining Methods

Zone electrophoresis on starch gel in conjunction with various histochemical staining methods was applied to the study of the water-soluble esterases of liver. The results indicated that in regard to electrophoretic migration and enzymatic properties, none of the human liver esterases was identical with any of the human serum esterases.

scholarly journals Effect of temperature and pH on carbamoylation and phosphorylation of serum cholinesterases. Theoretical interpretation of activation energies in complex reactions

1972 ◽  
Vol 130 (2) ◽  
pp. 515-524 ◽  
Author(s):  
V. Simeon ◽  
E. Reiner ◽  
C. A. Vernon
Keyword(s):  
Human Serum ◽  
Rate Constants ◽  
Time Course ◽  
Organophosphorus Compounds ◽  
Horse Serum ◽  
Bimolecular Reaction ◽  
Effect Of Temperature ◽  
Theoretical Interpretation ◽  
Serum Cholinesterase ◽  
Kinetics Of

1. The effect of temperature and pH was studied on the kinetics of inhibition of horse serum and human serum cholinesterase by four organophosphorus compounds and five carbamates. 2. For all compounds, and at each pH and temperature, the inhibition followed the kinetics of a bimolecular reaction with the inhibitor in excess, and with a negligible concentration of the Michaelis complex. 3. The second-order rate constants (ka) for inhibition of human serum cholinesterase by one organophosphate and one carbamate increased from 5° to 40°C with an apparent activation energy of 46kJ/mol (11kcal/mol). 4. The ka constant for inhibition of horse serum cholinesterase increased with temperature from 5° to 30°C, and then decreased from 30° to 40°C. The theoretical interpretation of such an unusual effect of temperature is derived. 5. The increase of ka with pH (human serum cholinesterase) followed the dissociation curve for a single group on the enzyme (pK7.5). 6. Rate constants for decarbamoylation (k+3) were determined, and the time-course of inhibition was calculated from the ka and k+3 constants.

Megaselia scalaris (Lw.) (Dipt., Phoridae) for the bioassay of organophosphorus insecticides

1969 ◽  
Vol 59 (3) ◽  
pp. 389-392
Author(s):  
Syed S. H. Qadri
Keyword(s):  
Drosophila Melanogaster ◽  
Organophosphorus Compounds ◽  
Simple Procedure ◽  
Mass Rearing ◽  
The Other ◽  
Organophosphorus Insecticides ◽  
Old Adults ◽  
Megaselia Scalaris ◽  
Mixed Populations ◽  
Different Order

A simple procedure for mass-rearing Megaselia scalaris (Lw.) is described, and the suitability of one-day-old adults for bioassay of organophosphorus insecticides is compared with that of Drosophila melanogaster Mg., and Musca domestica nebulo F. by exposure to films of parathion, dichlorvos and malathion. LC50 values of Megaselia scalaris for parathion and malathion, but not for dichlorvos, were of a different order to those of the other two test insects. Males were more susceptible than females to parathion and malathion. Mixed populations would therefore be useful in bioassay of organophosphorus compounds, but greater sensitivity would be achieved by using males.

L-p-Bromotetramisole, a new reagent for use in measuring placental or intestinal isoenzymes of alkaline phosphatase in human serum.

1977 ◽  
Vol 23 (3) ◽  
pp. 454-459 ◽  
Author(s):  
H Van Belle ◽  
M E De Broe ◽  
R J Wieme
Keyword(s):  
Alkaline Phosphatase ◽  
Pregnant Women ◽  
Human Serum ◽  
Blood Donors ◽  
Hospitalized Patients ◽  
The Other ◽  
Low Concentrations

Abstract L-p-Bromotetramisole is proposed as a new reagent for use in determining intestinal and (or) placental isoenzymes of alkaline phosphatase in human serum. Its main advantage over L-phenylalanine is its high discriminating potency at very low concentrations. For highest accuracy, the samples may even be "titrated" with the inhibitor. Analytical recoveries of intestinal and placental isoenzymes in serum are complete, and results correlate well with those by other methods. At the appropriate concentrations, L-p-bromotetramisole gives nearly identical results on a variety of sera, irrespective of the buffer used. Within-day CV's were 6.1 and 2.1 for 20% and 60% of the resistant isoenzyme activity, respectively. The day-to-day CV was 3.45 for a sample containing 53.3% of the resistant isoenzyme (n=15). The well-known increase in placental isoenzyme activity with time of gestation could be confirmed on 612 sera from pregnant women. The activities of the intestinal isoenzyme in sera from healty blood donors (n = 126) and hospitalized patients (n = 135) agree with previous findings obtained by the other techniques.

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