Pathobiochemistry of ammonia in the internal environment of fish (Review)
2002
Smutna, M. | Vorlova, L. | Svobodova, Z. (Veterinarni a Farmaceuticka Univ., Brno (Czech Republic). Ustav Biochemie a Biofyziky)
In this study, the origin and pathways of detoxication of ammonia in the body of fish are analyzed. The role of direct deamination of histidine, serine, asparagine and glutamine is emphasized with regard to ammonia production. The functional association of transamination and deamination is reflected in a transdeamination reaction, where the central role is played by the enzyme glutamate dehydrogenase. Furthemore, less known sources of ammonia occurring during natural restoration of body cells and tissues are discussed. Particularities of biochemical processes in fish, such as the non-existence of ureosynthetic cycle along with a sudden change of environmental conditions can easily disturb the balance between production and excretion. If the detoxication abilities of fish are exceedeed, ammonia acts as a toxicant, thus leading to accidental mortalities of fish.
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