Answer to Question #188958 in Chemistry for Almira

Question

1. What is the fate of proteases after their role in protein digestion?

2. Why is arginine classified as an essential amino acid in humans when it is synthesized in the urea cycle?

3. How do higher organisms obtain ammonia?

Answer 1

1. After several rounds of the catalysis (protein digestion), proteases denature and are hydrolyzed (digested) by the same or other proteases. The amino acids produced during the hydrolysis are absorbed in the intestine and are further used in the protein synthesis.

2. Although arginine is synthesized in the urea cycle, it is further used to produce urea and start the urea cycle again. On the other hand, arginine is used as a precursor of multiple biomolecules (i.e., nitrogen oxide, creatine and polyamines). As a result, arginine is rapidly used by the cells and irreversibly transformed into other biomolecules.

3. In higher organisms, ammonia is derived from the amino groups present in amino acids. Some processes of amino acids deamination are associated with the production of ammonia.