In the liver, the relative activity of ornithine transcarbamylase is high, that of argininosuccinate synthetase is low, and that of arginase is high. Why is it important that ornithine transcarbamylase activity be high in the liver? What might be the consequence if arginase activity is low or defective?
Enzyme kinetics
In biochemistry, enzymes are proteins that act as biological catalysts. Catalysis is the addition of a catalyst to a chemical reaction to speed up the pace of the reaction. Catalysis can be categorized as either homogeneous or heterogeneous, depending on whether the catalysts are distributed in the same phase as that of the reactants. Enzymes are an essential part of the cell because, without them, many organic processes would slow down and thus will affect the processes that are important for cell survival and sustenance.
Regulation of Enzymes
A substance that acts as a catalyst to regulate the reaction rate in the living organism's metabolic pathways without itself getting altered is an enzyme. Most of the biological reactions and metabolic pathways in the living systems are carried out by enzymes. They are specific for their works and work in particular conditions. It maintains the best possible rate of reaction in the most stable state. The enzymes have distinct properties as they can proceed with the reaction in any direction, their particular binding sites, pH specificity, temperature specificity required in very few amounts.
In the liver, the relative activity of ornithine transcarbamylase is high, that of argininosuccinate synthetase is low, and that of arginase is high. Why is it important that ornithine transcarbamylase activity be high in the liver? What might be the consequence if arginase activity is low or defective?
Ornithine transcarbamylase is the enzyme that catalyzes the conversion of carbamyl phosphate and ornithine to citrulline and phosphate as a part of a catabolic reaction for proteins. This enzyme also works in the anabolic process for the biosynthesis of arginine. The activity of this enzyme is high in liver mitochondria.
- The activity of ornithine transcarbamylase is high because it is used in both anabolic and catabolic processes.
- The activity of arginase is high in the liver. It catalyzes the conversion of arginine to urea and ornithine. A defect in this enzyme leads to the accumulation of arginine and ammonia in the body.
- Ammonia is toxic to the body, so high levels are not desirable.
- High arginine can make previous symptoms of herpes worse leading to cold sores and outbreaks.
- Other possible symptoms of high arginine are abdominal pain, bloating, diarrhoea, and gout.
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