STEREOSPECIFICITY IN THE ENZYMATIC HYDROLYSIS OF TABUN AND ACETYL-β-METHYLCHOLINE CHLORIDE

1955 ◽  
Vol 33 (1) ◽  
pp. 963-969 ◽  
Author(s):  
F. C. G. Hoskin ◽  
G. S. Trick
Keyword(s):  
Enzymatic Hydrolysis ◽  
Enzymatic Reaction ◽  
Brain Homogenate ◽  
Serum Enzyme ◽  
Rat Serum ◽  
Bicarbonate Buffer ◽  
First Order ◽  
Acetylcholine Chloride ◽  
Hydrolysis Of ◽  
Enzyme Source

The hydrolysis of the powerful cholinesterase inhibitor, tabun, at pH 7 to 7.5 by a rat serum enzyme in bicarbonate buffer involves two simultaneous first-order reactions. A fast, enzyme-catalyzed reaction destroys the toxic dextrorotatory isomer of tabun. The much slower hydrolysis of the levorotatory and apparently non-toxic isomer is probably a non-enzymatic reaction. The enzymatic hydrolysis of acetyl-dl-β-methylcholine chloride by a rat brain homogenate has been studied as a model reaction. Only one-half of the racemic compound is hydrolyzed in contrast to the complete hydrolysis of acetylcholine chloride by the same enzyme source. These results and the results of toxicity studies on the hydrolyzing solution indicate that true cholinesterase hydrolyzes only the dextrorotatory isomer of acetyl-dl-β-methylcholine chloride.

STEREOSPECIFICITY IN THE ENZYMATIC HYDROLYSIS OF TABUN AND ACETYL-β-METHYLCHOLINE CHLORIDE

1955 ◽  
Vol 33 (6) ◽  
pp. 963-969 ◽  
Author(s):  
F. C. G. Hoskin ◽  
G. S. Trick
Keyword(s):  
Enzymatic Hydrolysis ◽  
Enzymatic Reaction ◽  
Brain Homogenate ◽  
Serum Enzyme ◽  
Rat Serum ◽  
Bicarbonate Buffer ◽  
First Order ◽  
Acetylcholine Chloride ◽  
Hydrolysis Of ◽  
Enzyme Source

The hydrolysis of the powerful cholinesterase inhibitor, tabun, at pH 7 to 7.5 by a rat serum enzyme in bicarbonate buffer involves two simultaneous first-order reactions. A fast, enzyme-catalyzed reaction destroys the toxic dextrorotatory isomer of tabun. The much slower hydrolysis of the levorotatory and apparently non-toxic isomer is probably a non-enzymatic reaction. The enzymatic hydrolysis of acetyl-dl-β-methylcholine chloride by a rat brain homogenate has been studied as a model reaction. Only one-half of the racemic compound is hydrolyzed in contrast to the complete hydrolysis of acetylcholine chloride by the same enzyme source. These results and the results of toxicity studies on the hydrolyzing solution indicate that true cholinesterase hydrolyzes only the dextrorotatory isomer of acetyl-dl-β-methylcholine chloride.

THE ENZYMATIC HYDROLYSIS PRODUCTS OF SARIN

1956 ◽  
Vol 34 (1) ◽  
pp. 75-79 ◽  
Author(s):  
F. C. G. Hoskin
Keyword(s):  
Enzymatic Hydrolysis ◽  
Cholinesterase Inhibitor ◽  
Methylphosphonic Acid ◽  
Serum Enzyme ◽  
Rat Serum ◽  
Hydrolysis Products ◽  
Hydrolysis Of

The hydrolysis of the powerful cholinesterase inhibitor, sarin, by a rat serum enzyme leads almost exclusively to isopropyl methylphosphonic acid, neither methylphosphonic acid nor hydrogen methylphosphonofluoridate being formed. When isopropyl methylphosphonic acid is administered to the intact rat, it is excreted unchanged in the urine. It is inferred, therefore, that the metabolism of sarin by the intact rat would lead almost exclusively to isopropyl methylphosphonic acid.

THE ENZYMATIC HYDROLYSIS PRODUCTS OF SARIN

1956 ◽  
Vol 34 (1) ◽  
pp. 75-79 ◽  
Author(s):  
F. C. G. Hoskin
Keyword(s):  
Enzymatic Hydrolysis ◽  
Cholinesterase Inhibitor ◽  
Methylphosphonic Acid ◽  
Serum Enzyme ◽  
Rat Serum ◽  
Hydrolysis Products ◽  
Hydrolysis Of

The hydrolysis of the powerful cholinesterase inhibitor, sarin, by a rat serum enzyme leads almost exclusively to isopropyl methylphosphonic acid, neither methylphosphonic acid nor hydrogen methylphosphonofluoridate being formed. When isopropyl methylphosphonic acid is administered to the intact rat, it is excreted unchanged in the urine. It is inferred, therefore, that the metabolism of sarin by the intact rat would lead almost exclusively to isopropyl methylphosphonic acid.

scholarly journals Enzymatic hydrolysis of oil palm empty fruit bunch to produce reducing sugar and its kinetic Hidrolisis enzimatik tandan kosong kelapa sawit untuk menghasilkan gula pereduksi dan kinetikanya

2016 ◽  
Vol 83 (1) ◽  
Author(s):  
Vera BARLIANTI ◽  
Deliana DAHNUM ◽  
. MURYANTO ◽  
Eka TRIWAHYUNI ◽  
Yosi ARISTIAWAN ◽  
...  
Keyword(s):  
Enzymatic Hydrolysis ◽  
Oil Palm ◽  
Volume Ratio ◽  
Enzyme Concentration ◽  
Reducing Sugar ◽  
Economic Feasibility ◽  
First Order ◽  
Empty Fruit Bunches ◽  
Hydrolysis Process ◽  
Hydrolysis Of

Abstrak Sebagai salah satu Negara penghasil minyak kelapa sawit mentah (CPO), Indonesia juga menghasilkan tandan kosong kelapa sawit (TKKS) dalam jumlah besar. TKKS terdiri dari-tiga-komponen utama, yaitu selulosa, hemiselulosa, dan lignin. Pengolahan awal TKKS secara alkalindi ikuti dengan hidrolisis TKKS secara enzimatik menggunakan kombinasi enzim selulase dan β-glukosidase akan menghasilkan gula-gula yang mudah difermentasi.  Penelitian ini bertujuan untuk mempelajari pengaruh konsentrasi substrat, kon-sentrasi enzim, dan suhu selama proses hidrolisis berlangsung.  Hasil yang diperoleh menunjukkan bahwa konsentrasi gula maksimum (194,78 g/L) dicapai pada konsentrasi TKKS 20% (b/v), konsentrasi campuran enzim yang terdiri dari selulase dan β-1,4 glukosidase sebesar 3,85% (v/v), dan suhu 50oC. Perbandingan antara selulase dan β-1,4 glukosidase adalah 5:1 dengan masing-masing aktivitas enzim sebesar 144.5 FPU/mL dan 63 FPU/mL. Hasil penelitian juga menunjukkan bahwa model kinetika yang sesuai untuk proses hidrolisis TKKS secara enzimatik adalah model kinetika Shen dan Agblevor dengan reakside aktivasi enzim orde satu.  Hasil ini mendukung studi kelayakan ekonomi dalam pemanfaatan TKKS untuk produksi bioetanol.AbstractAs one of the crude palm oil producers, Indonesia also produces empty fruit bunches (EFB)in large quantities. The oil palm EFB consist of cellulose, hemicellulose and lignin. Alkaline pretreatment of EFB, followed by enzymatic hydro-lysis of cellulose using combination of cellulase and β-glucosidase enzymes produce fermentable sugars. This paper reported the effects of substrate loading, enzyme concentration, and temperature of hydrolysis process on reducing sugar production. The  maximum  sugar  concentration (194.78 g/L) was produced at 50oC using 20% (w/v) EFB and 3.85% (v/v) mixed enzymes of cellulase and β-1,4 glucosidase in volume ratio of 5:1 (v/v), with enzyme activity of 144.5 FPU/mL and 63 FPU/mL, respectively. The results also showed that the suitable kinetic model for enzymatic hydrolysis process of oil palm EFB follow Shen and Agblevor model with first order of enzyme deactivation. These results support the economic feasibility study in utilization of EFB of oil palm for bioethanol production.    

scholarly journals Effects of sonication and high-pressure carbon dioxide processing on enzymatic hydrolysis of egg white proteins

2012 ◽  
pp. 33-41 ◽  
Author(s):  
Zorica Knezevic-Jugovic ◽  
Andrea Stefanovic ◽  
Milena Zuza ◽  
Stoja Milovanovic ◽  
Sonja Jakovetic ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Antioxidant Activity ◽  
High Pressure ◽  
Enzymatic Hydrolysis ◽  
Enzymatic Reaction ◽  
Egg White ◽  
Degree Of Hydrolysis ◽  
Egg White Proteins ◽  
Hydrolysis Of ◽  
Ultrasound Pretreatment

The objectives of this study were to examine the effect of sonication and high-pressure carbon dioxide processing on proteolytic hydrolysis of egg white proteins and antioxidant activity of the obtained hydrolysates. It appeared that the ultrasound pretreatment resulted in an increase in the degree of hydrolysis of the enzymatic reaction while the high-pressure carbon dioxide processing showed an inhibition effect on the enzymatic hydrolysis of egg white proteins to some extent. The antioxidant activity of the obtained hydrolysates was improved by ultrasound pretreatment of egg white proteins at the pH 8.3. Thus, the combination of ultrasound pretreatment at the pH 8.3 and subsequent enzymatic hydrolysis with alcalase at 50?C and pH 8.0 could offer a new approach to the improvement of the functional properties of egg white proteins and their biological activity.

KINETICS OF THE ENZYMATIC HYDROLYSIS OF SARIN

1956 ◽  
Vol 34 (1) ◽  
pp. 80-82 ◽  
Author(s):  
P. A. Adie ◽  
F. C. G. Hoskin ◽  
G. S. Trick
Keyword(s):  
Enzymatic Hydrolysis ◽  
Reaction Rates ◽  
Order Reaction ◽  
First Order Reaction ◽  
Optical Isomers ◽  
First Order ◽  
Kinetics Of ◽  
Hydrolysis Of

The enzymatic hydrolysis of sarin is apparently a single first-order reaction. There is no evidence of different reaction rates for the two possible optical isomers of sarin. During both the enzymatic and the non-enzymatic hydrolyses, sarin appears to be detoxified somewhat more rapidly than the manometric results would indicate. However, the detoxification parallels the manometric results sufficiently to stand in contrast to results obtained using tabun.

THE NON-ENZYMATIC HYDROLYSIS OF ADENOSINE DIPHOSPHATE

1957 ◽  
Vol 35 (12) ◽  
pp. 1496-1503 ◽  
Author(s):  
K. A. Holbrook ◽  
Ludovic Ouellet
Keyword(s):  
Activation Energy ◽  
Aqueous Solution ◽  
Enzymatic Hydrolysis ◽  
Inorganic Phosphate ◽  
Adenosine Diphosphate ◽  
Hydrogen Ions ◽  
Kcal Mole ◽  
First Order ◽  
Kinetics Of ◽  
Hydrolysis Of

The kinetics of the non-enzymatic hydrolysis of adenosine diphosphate in aqueous solution have been studied at pH 3.5 to 10.5 and temperatures from 80° to 95 °C. The reaction has been followed by measuring colorimetrically the inorganic phosphate liberated according to the over-all reaction[Formula: see text]The reaction has been found to be first order with respect to ADP concentration and to be catalyzed by hydrogen ions. From rate studies at pH 8.0 an activation energy of 24.2 kcal./mole was derived. A mechanism is proposed to account for the observed facts and the mechanism for the hydrolysis of adenosine triphosphate is also discussed.

THE NON-ENZYMATIC HYDROLYSIS OF p-NITROPHENYL PHOSPHATE

1958 ◽  
Vol 36 (4) ◽  
pp. 686-690 ◽  
Author(s):  
K. A. Holbrook ◽  
Ludovic Ouellet
Keyword(s):  
Activation Energy ◽  
Enzymatic Hydrolysis ◽  
Ionic Species ◽  
Kcal Mole ◽  
First Order ◽  
Colorimetric Measurement ◽  
Nitrophenyl Phosphate ◽  
Ph Range ◽  
Kinetics Of ◽  
Hydrolysis Of

The kinetics of the non-enzymatic hydrolysis of p-nitrophenyl phosphate have been studied in aqueous solution in the pH range 2.6 to 9.0 and at temperatures from 68.0°to 82.0 °C. The reaction has been followed by colorimetric measurement of the nitrophenol produced by the reaction[Formula: see text]The reaction is first order with respect to p-nitrophenyl phosphate and has an activation energy of 26.0 kcal./mole at pH 2.6. An explanation has been proposed in terms of the different rates of hydrolysis of the various ionic species of the ester present in solution.

KINETICS OF THE ENZYMATIC HYDROLYSIS OF SARIN

1956 ◽  
Vol 34 (1) ◽  
pp. 80-82 ◽  
Author(s):  
P. A. Adie ◽  
F. C. G. Hoskin ◽  
G. S. Trick
Keyword(s):  
Enzymatic Hydrolysis ◽  
Reaction Rates ◽  
Order Reaction ◽  
First Order Reaction ◽  
Optical Isomers ◽  
First Order ◽  
Kinetics Of ◽  
Hydrolysis Of

The enzymatic hydrolysis of sarin is apparently a single first-order reaction. There is no evidence of different reaction rates for the two possible optical isomers of sarin. During both the enzymatic and the non-enzymatic hydrolyses, sarin appears to be detoxified somewhat more rapidly than the manometric results would indicate. However, the detoxification parallels the manometric results sufficiently to stand in contrast to results obtained using tabun.

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