Asparagine, deamination from glutamine

Two amino acids—asparagine and glutamine—contain acid-amide groups in the side chains, from which NH3 can be released by hydrolysis (hydrolytic deamination). In the blood, glutamine is the most important transport molecule for amino nitrogen. Hydrolytic deamination of glutamine in the liver also supplies the urea cycle with NH3. 

The liberated amino acids may be used for protein synthesis, or to provide energy by oxidation of the carbon skeleton after deamination. Ammonia produced in the latter reaction can be prevented from reaching toxic levels by fixation into glutamine and asparagine. 

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