Urea output by L3 Teladorsagia circumcincta and some properties of two urea producing enzymes

Muhamad, N., Walker, L.R., Simcock, D.C., Pedley, K.C., Simpson, H.V., and Brown, S. (2013) Urea output by L3 Teladorsagia circumcincta and some properties of two urea producing enzymes. Iranian Journal of Parasitology, 8 (1). pp. 137-144.

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Abstract

Background: Like several other parasites, Teladorsagia circumcincta secretes or excretes urea, but nei­ther the rate of efflux nor the possible metabolic sources of the urea has been considered.

Methods: Parasites were maintained by passage through sheep. Urea efflux was measured using phe­nol/hypochlorite after treatment with urea aminohydrolase. The kinetics of creatine amidinohy­drolase and arginine amidinohydrolase were characterised by coupling the reactions with urea aminohy­drolase and glutamate dehydrogenase.

Results: Infective L3 T. circumcincta secreted or excreted urea at 25% of the rate of NH3/NH­4+. The rate of urea efflux was about 84 pmol h‑1 (103 larvae)‑1 over 4 hours, corresponding to about 11 nmol h-1 mg-1 protein. We could not detect urea aminohydrolase activity, but urea production by both creatine amidinohydrolase and arginine amidinohydrolase could be detected. The apparent Km and Vmax of creatine amidinohydrolase were 1.1 mM and 48 nmol h-1 mg-1 protein, respectively, and the activity was greatest at pH 8. The apparent Km and Vmax of arginine amidinohydrolase were 0.7 mM and 62 nmol h-1 mg-1 protein, respectively, and the activity was greatest at pH 7.9.

Conclusion: The activity of creatine amidinohydrolase and arginine amidinohydrolase was sufficient to account for the rate of urea secretion or excretion.

Item ID: 35749
Item Type: Article (Research - C1)
ISSN: 1735-7020
Keywords: kinetics, Teladorsagia circumcincta, urea
Additional Information:

This work is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License which allows users to read, copy, distribute and make derivative works for non-commercial purposes from the material, as long as the author of the original work is cited properly.

Date Deposited: 15 Oct 2014 16:48
FoR Codes: 06 BIOLOGICAL SCIENCES > 0601 Biochemistry and Cell Biology > 060104 Cell Metabolism @ 50%
07 AGRICULTURAL AND VETERINARY SCIENCES > 0707 Veterinary Sciences > 070708 Veterinary Parasitology @ 50%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970106 Expanding Knowledge in the Biological Sciences @ 50%
97 EXPANDING KNOWLEDGE > 970107 Expanding Knowledge in the Agricultural and Veterinary Sciences @ 50%
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