Humans produce this compound because ammonia is too toxic to excrete.
The concentration of this substance in the blood is measured in BUN levels. It's not a pyrimidine, but carbamoyl phosphate is produced in the beginning of a reaction that results in this compound. The enzyme arginase produces the amino acid ornithine in addition to this compound when it acts on arginine. Silver cyanate was reacted with ammonium chloride in an experiment by (*) Friedrich Woehler, which produced this compound from inorganic reactants. Humans produce this compound because ammonia is too toxic to excrete. For ten points, name this nitrogenous compound which is found in mammalian urine.
The concentration of this substance in the blood is measured in BUN levels.
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