scholarly journals The Comparative Metabolism of Some Substituted Phenyl-N-Methylcarbamate Insecticides

2021 ◽  
Author(s):  
◽  
Philip Geoffrey Charles Douch
Keyword(s):  
Musca Domestica ◽  
Enzyme System ◽  
Enzymic Hydrolysis ◽  
Selective Toxicity ◽  
Mouse Blood ◽  
Carbamate Insecticides ◽  
Comparative Metabolism ◽  
Costelytra Zealandica ◽  
Oxidative Products ◽  
Hydrolysis Of

<p>1. The metabolism of the N-methylcarbamates of 3-tertbutylphenol; 3,5-ditertbutylphenol; and 2-isopropoxyphenol was investigated in insects and mammals. 2. The major degradative pathway in enzyme systems from insects and mice was oxidative. The major metabolites from tertbutyl substituted phenyl-N-methylcarbamates were N-hydroxymethyl derivatives and tertbutanol derivatives. Baygon yielded N-hydroxymethyl, ring hydroxyl and O-dealkyl derivatives as major metabolites. 3. The rates of oxidation of the three insecticides in each enzyme system were similar. 4. Oxidation was inhibited by piperonyl butoxide and Metopirone, apparent I50 for singly oxidised metabolites was 10-4 M, and for metabolites with two oxidations 10-5M. 5. Enzymic hydrolysis of carbamate insecticides required reduced cofactor in insect and mouse systems. Mouse blood did not effect hydrolysis. 6. A wide variation of oxidising ability was found in live insects. Musca domestica was most active, Tenebrio molitor and Costelytra zealandica were least active. 7. Insecticide synergists reduce insects' ability to oxidise Baygon to acetone. 8. Musca domestica and Lucilia sericata larvae oxidised carbamate insecticides slower than the adult forms. 9. Mice excrete 3-tertbutylphenyl-N-methylcarbamate as phenolic metabolites, with only minor oxidative products. 10. Different rates of metabolism among insects could account for the selective toxicity of aryl-N-methylcarbamates.</p>

scholarly journals The Comparative Metabolism of Some Substituted Phenyl-N-Methylcarbamate Insecticides

2021 ◽  
Author(s):  
◽  
Philip Geoffrey Charles Douch
Keyword(s):  
Musca Domestica ◽  
Enzyme System ◽  
Enzymic Hydrolysis ◽  
Selective Toxicity ◽  
Mouse Blood ◽  
Carbamate Insecticides ◽  
Comparative Metabolism ◽  
Costelytra Zealandica ◽  
Oxidative Products ◽  
Hydrolysis Of

<p>1. The metabolism of the N-methylcarbamates of 3-tertbutylphenol; 3,5-ditertbutylphenol; and 2-isopropoxyphenol was investigated in insects and mammals. 2. The major degradative pathway in enzyme systems from insects and mice was oxidative. The major metabolites from tertbutyl substituted phenyl-N-methylcarbamates were N-hydroxymethyl derivatives and tertbutanol derivatives. Baygon yielded N-hydroxymethyl, ring hydroxyl and O-dealkyl derivatives as major metabolites. 3. The rates of oxidation of the three insecticides in each enzyme system were similar. 4. Oxidation was inhibited by piperonyl butoxide and Metopirone, apparent I50 for singly oxidised metabolites was 10-4 M, and for metabolites with two oxidations 10-5M. 5. Enzymic hydrolysis of carbamate insecticides required reduced cofactor in insect and mouse systems. Mouse blood did not effect hydrolysis. 6. A wide variation of oxidising ability was found in live insects. Musca domestica was most active, Tenebrio molitor and Costelytra zealandica were least active. 7. Insecticide synergists reduce insects' ability to oxidise Baygon to acetone. 8. Musca domestica and Lucilia sericata larvae oxidised carbamate insecticides slower than the adult forms. 9. Mice excrete 3-tertbutylphenyl-N-methylcarbamate as phenolic metabolites, with only minor oxidative products. 10. Different rates of metabolism among insects could account for the selective toxicity of aryl-N-methylcarbamates.</p>

THE WHEAT LEAF PHOSPHATASES: VI. SOME PROPERTIES OF THE ENZYME SYSTEM HYDROLYZING ADENOSINE-5′-PHOSPHATE AND PHENOLPHTHALEIN DIPHOSPHATE IN CRUDE JUICE PREPARATIONS

1963 ◽  
Vol 41 (5) ◽  
pp. 1275-1281 ◽  
Author(s):  
D. W. A. Roberts
Keyword(s):  
Enzyme System ◽  
The Other ◽  
Enzymic Hydrolysis ◽  
Ph Optimum ◽  
Wheat Leaf ◽  
Hydrolysis Of ◽  
Leaf Juice

At least two enzymes are probably involved in the hydrolysis of mixtures of β-glycerophosphate, phenolphthalein diphosphate, and adenosine-5′-phosphate. One enzyme is primarily responsible for the hydrolysis of β-glycerophosphate whereas the other enzyme hydrolyzes adenosine-5′-phosphate and phenolphthalein diphosphate but has little activity on β-glycerophosphate.The liberation of orthophosphate from adenosine-5′-phosphate and phenolphthalein diphosphate by the enzyme in wheat leaf juice is inhibited by 0.005 M adenosine but not by 0.02 M phosphate. The inhibition of this enzyme by fluoride is markedly smaller than the inhibition of β-glycerophosphatase. The enzyme that hydrolyzes phenolphthalein diphosphate transfers phosphate from phenolphthalein diphosphate to adenosine to form adenosine-5′-phosphate.Experiments on the pH optimum for the enzymic hydrolysis of both adenosine-5′-phosphate and phenolphthalein diphosphate by undialyzed and dialyzed juice preparations with or without added Mg++ suggest that there may be more than one enzyme with different pH optima acting on both adenosine-5′-phosphate and phenolphthalein diphosphate.

THE WHEAT LEAF PHOSPHATASES: VI. SOME PROPERTIES OF THE ENZYME SYSTEM HYDROLYZING ADENOSINE-5′-PHOSPHATE AND PHENOLPHTHALEIN DIPHOSPHATE IN CRUDE JUICE PREPARATIONS

1963 ◽  
Vol 41 (1) ◽  
pp. 1275-1281 ◽  
Author(s):  
D. W. A. Roberts
Keyword(s):  
Enzyme System ◽  
The Other ◽  
Enzymic Hydrolysis ◽  
Ph Optimum ◽  
Wheat Leaf ◽  
Hydrolysis Of ◽  
Leaf Juice

At least two enzymes are probably involved in the hydrolysis of mixtures of β-glycerophosphate, phenolphthalein diphosphate, and adenosine-5′-phosphate. One enzyme is primarily responsible for the hydrolysis of β-glycerophosphate whereas the other enzyme hydrolyzes adenosine-5′-phosphate and phenolphthalein diphosphate but has little activity on β-glycerophosphate.The liberation of orthophosphate from adenosine-5′-phosphate and phenolphthalein diphosphate by the enzyme in wheat leaf juice is inhibited by 0.005 M adenosine but not by 0.02 M phosphate. The inhibition of this enzyme by fluoride is markedly smaller than the inhibition of β-glycerophosphatase. The enzyme that hydrolyzes phenolphthalein diphosphate transfers phosphate from phenolphthalein diphosphate to adenosine to form adenosine-5′-phosphate.Experiments on the pH optimum for the enzymic hydrolysis of both adenosine-5′-phosphate and phenolphthalein diphosphate by undialyzed and dialyzed juice preparations with or without added Mg++ suggest that there may be more than one enzyme with different pH optima acting on both adenosine-5′-phosphate and phenolphthalein diphosphate.

Variation in Quantity of Methanol Recovered from Raisins

1963 ◽  
Vol 46 (2) ◽  
pp. 341-343
Author(s):  
M Alice Brown ◽  
James R Woodward ◽  
Floyd DeEds
Keyword(s):  
Methyl Ester ◽  
Esterase Activity ◽  
Enzymic Hydrolysis ◽  
Methanol Content ◽  
Naturally Occurring ◽  
Pectin Esterase ◽  
Hydrolysis Of

Abstract The amount of naturally occurring methanol in fruit must be known so that the quantity left as fumigation residue can be determined. In a study of methanol content of raisins, which had given inconsistent results, the raisins were subjected to different conditions of treatment immediately prior to methanol determination. Conditions that favored pectin esterase activity gave higher values for methanol content than conditions known to inactivate enzymes. Evidence was also obtained that both chemical and enzymic hydrolysis of methyl ester groups of pectic materials occur during analysis.

scholarly journals Permeability of muscle capillaries to small heme-peptides. Evidence for the existence of patent transendothelial channels.

1975 ◽  
Vol 64 (3) ◽  
pp. 586-607 ◽  
Author(s):  
N Simionescu ◽  
M Siminoescu ◽  
G E Palade
Keyword(s):  
Plasma Proteins ◽  
Intercellular Junctions ◽  
Rat Diaphragm ◽  
Enzymic Hydrolysis ◽  
Graphic Analysis ◽  
Heme Peptides ◽  
Future Work ◽  
Hydrolysis Of ◽  
Muscle Capillaries

Two heme-peptides (HP) of about 20-A diameter (heme-undecapeptide [H11P], mol wt approximately 1900 and heme-octapeptide [H8P], mol wt approximately 1550), obtained by enzymic hydrolysis of cytochrome c, were sued as probe molecules in muscle capillaries (rat diaphragm). They were localized in situ by a perixidase reaction, enhanced by the addition of imidazole to the incubation medium. Chromatography of plasma samples showed that HPs circulate predominantly as monomers for the duration of the experiments and are bound by aldehyde fixatives to plasma proteins to the extent of approximately 50% (H8P) to approximately 95% (H11P). Both tracers cross the endothelium primarily via plasmalemmal vesicles which become progressively labeled (by reaction product) from the blood front to the tissue front of the endothelium, in three successive resolvable phases. By the end of each phase the extent of labeling reaches greater than 90% of the corresponding vesicle population. Labeled vesicles appear as either isolated units or chains which form patent channels across the endothelium. The patency of these channels was checked by specimen tilting and graphic analysis of their images. No evidence was found for early or preferential marking of the intercellular junctions and spaces by reaction product. It is concluded that the channels are the most likely candidate for structural equivalents of the small pores of the capillary wall since they are continuous, water-filled passages, and are provided with one or more strictures of less than 100 A. Their frequency remains to be established by future work.

Investigation of the products of an enzymic hydrolysis of collagens

Biochemistry ◽  
1969 ◽  
Vol 8 (12) ◽  
pp. 4716-4723 ◽  
Author(s):  
Howard B. Bensusan
Keyword(s):  
Enzymic Hydrolysis ◽  
Hydrolysis Of

scholarly journals Constancy of the optimum temperature of an enzyme under varying concentrations of substrate and of enzyme

1914 ◽  
Vol 88 (602) ◽  
pp. 258-262
Keyword(s):  
Experimental Evidence ◽  
Aspergillus Oryzae ◽  
Hydrolytic Enzyme ◽  
Fixed Duration ◽  
Optimum Temperature ◽  
Enzymic Hydrolysis ◽  
Main Interest ◽  
General Law ◽  
The Moment ◽  
Hydrolysis Of

In a recent paper a new enzymic relation is recorded. For the enzymic hydrolysis of salicin—by the enzyme which Gabriel Bertrand and the author have named salicinase —it is found that, in an action of fixed duration, the temperature of greatest activity of the ferment is always the same, whatever the dilutions of substrate and of enzyme adopted for the determination. In other words, the duration of the action being constant, the optimum tem­perature of the ferment is independent of the concentration both of the substrate and of the enzyme. The observation is suggestive: if true of one enzyme it may be true of all, and possibly becomes the enunciation of a general law. Herein, for the moment, lies its main interest. In the present paper further experimental evidence for this hypothesis in given, in the case of another hydrolytic enzyme, the maltase of Aspergillus oryzæ (taka-diastase).

Covalent attachment of amino acids to casein. 1. Chemical modification and rates of in vitro enzymic hydrolysis of derivatives

1979 ◽  
Vol 27 (5) ◽  
pp. 1098-1104 ◽  
Author(s):  
Antoine J. Puigserver ◽  
Lourminia C. Sen ◽  
Elvira Gonzales-Flores ◽  
Robert E. Feeney ◽  
John R. Whitaker
Keyword(s):  
Amino Acids ◽  
Chemical Modification ◽  
Covalent Attachment ◽  
Enzymic Hydrolysis ◽  
Hydrolysis Of

Enzyme system of Clostridium stercorarium for hydrolysis of arabinoxylan: reconstitution of the in vivo system from recombinant enzymes

Microbiology ◽  
2004 ◽  
Vol 150 (7) ◽  
pp. 2257-2266 ◽  
Author(s):  
Helmuth Adelsberger ◽  
Christian Hertel ◽  
Erich Glawischnig ◽  
Vladimir V. Zverlov ◽  
Wolfgang H. Schwarz
Keyword(s):  
Extracellular Enzymes ◽  
Enzyme System ◽  
Thermophilic Bacterium ◽  
Recombinant Enzymes ◽  
Type Mode ◽  
Complete Set ◽  
First Time ◽  
Hydrolysis Of

Four extracellular enzymes of the thermophilic bacterium Clostridium stercorarium are involved in the depolymerization of de-esterified arabinoxylan: Xyn11A, Xyn10C, Bxl3B, and Arf51B. They were identified in a collection of eight clones producing enzymes hydrolysing xylan (xynA, xynB, xynC), β-xyloside (bxlA, bxlB, bglZ) and α-arabinofuranoside (arfA, arfB). The modular enzymes Xyn11A and Xyn10C represent the major xylanases in the culture supernatant of C. stercorarium. Both hydrolyse arabinoxylan in an endo-type mode, but differ in the pattern of the oligosaccharides produced. Of the glycosidases, Bxl3B degrades xylobiose and xylooligosaccharides to xylose, and Arf51B is able to release arabinose residues from de-esterified arabinoxylan and from the oligosaccharides generated. The other glycosidases either did not attack or only marginally attacked these oligosaccharides. Significantly more xylanase and xylosidase activity was produced during growth on xylose and xylan. This is believed to be the first time that, in a single thermophilic micro-organism, the complete set of enzymes (as well as the respective genes) to completely hydrolyse de-esterified arabinoxylan to its monomeric sugar constituents, xylose and arabinose, has been identified and the enzymes produced in vivo. The active enzyme system was reconstituted in vitro from recombinant enzymes.

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