Abstract
Deactivation studies of jack bean urease immobilized on porous alumina beads in the hydrolysis of urea were conducted in a continuously stirred tank reactor (CSTR) at a temperature of 25°C and pH 7.0. Though the mechanism of poisoning of urease by product ammonia is fairly well understood from the literature, the nature of the poisoning of urease by urea is presented in this article. These studies were conducted by adsorbing the ammonia formed in the hydrolysis reaction. The results indicate that, in the presence of the adsorbent Zeolite W, the deactivation rate is reduced by a factor of almost two, and thus provide a technique for prolonging the life of the enzyme. The deactivation model suggests that the free form of the enzyme is most susceptible to attack by the substrate urea. The experimental data suggest that deactivation by combined ammonia and urea is fairly complex.
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Abbreviations
- a :
-
activity of the enzyme urease ([ET]0 / [E T]t)
- E :
-
free form of the enzyme urease
- [E T]:
-
total enzyme concentration, IU/g
- [E T]t :
-
total enzyme concentration at time t, IU/g
- [E T]0 :
-
total enzyme concentration at time t = 0, IU/g
- ES :
-
enzyme-substrate complex
- I :
-
inactive enzyme complex
- k d :
-
urea deactivation rate constant, (mM-min)-1
- k d ′ :
-
ammonia deactivation rate constant, (mM-min)-1
- K I :
-
urea inhibition constant, mM-1
- K I ′ :
-
ammonia inhibition constant, mM-1
- K m :
-
Michaelis constant,M
- n :
-
order of the deactivation rate equation
- P :
-
product ammonia
- [P]:
-
product (ammonia concentration), mM
- Q :
-
flow rate of feed solution used in each experiment, mL/min
- S :
-
substrate urea
- [S]:
-
substrate (urea) concentration, mM
- [S 0]:
-
feed urea concentration, mM
- V :
-
hydrolysis reaction rate, mmol/min
- v :
-
volume of reaction mixture in CSTR balance, mL
- V max :
-
maximum reaction rate velocity, IU/g
- V d :
-
deactivation reaction rate due to urea poisoning, min-1
- V d ′ :
-
deactivation reaction rate due to ammonia poisoning, min-1
- W :
-
weight of the immobilized enzyme used in each experiment, g.
References
Altomare, R. E., Greenfield, P. F., and Kittrell, J. R. (1974),Biotechnol. Bioeng. 16, 1675.
Altomare, R. E., Kohler, J., Greenfield, P. F., and Kittrell, J. R. (1974),Biotechnol. Bioeng. 16, 1659.
Greenfield, P. F., Kittrell, J. R., and Laurence, R. L. J. (1975),Anal. Biochem. 65, 109.
Krishnaswamy, S. and Kittrell, J. R. (1978),Biotechnol. and Bioeng. 20, 821.
Lin, S. H. (1977),Chem. Eng. J. 14, 129.
Tai, N. M. and Greenfield, P. F. (1981),Biotechnol. Bioeng. 23, 805.
Do, D. D. and Weiland, R. H. (1980),Biotechnol. Bioeng. 22, 1087.
Malikkides, C. O. and Weiland, R. H. (1982),Biotechnol. Bioeng. 24, 2419.
Vasudevan, P. T., Ruggiano, L., and Weiland, R. H. (1990),Biotechnol. Bioeng. 35, 1145.
Vasudevan, P. T. and Weiland, R. H. (1990),Biotechnol. Bioeng. 36, 783.
Vasudevan, P. T. and Thakur, D. S. (1994),Appl. Biochem. Biotechnol. 49, 173.
Cattaneo, M. V. and Chang, T. M. S. (1991),ASAIO Trans. 37, 80.
Mobley, H. L. T. and Hausinger, R. P. (1989),Microbiol. Rev. 53, 85.
Krajewska, B. (1991),J. Chem. Technol. Biotechnol. 52, 157.
Dixon, N. E., Gazzola, C., Blakeley, R. L., and Zerner, N. (1975),JACS 97, 4131.
Andrews, R. K., Blakeley, R. L., and Zerner, B. (1984), inAdvances in Inorganic Biochemistry, Vol. 6, Eichhorn, G. L. and Marzilli, L. G., eds., Elsevier Science, New York.
Todd, M. J. and Hausinger, R. P. (1989),JBC 264, 15835.
Ramchandran, K. B. (1975), PhD Dissertation, Univ. of Pennsylvania.
Hoare, J. P. and Laidler, K. J. (1950),J. Amer. Chem. Soc. 72, 2487.
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Vasdudevan, P.T., Gokarn, Y. Deactivation of jack bean urease in urea hydrolysis. Appl Biochem Biotechnol 60, 49–61 (1996). https://doi.org/10.1007/BF02788059
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DOI: https://doi.org/10.1007/BF02788059