Ornithine

Part of speech: noun

Definitions

1. An amino acid that plays a central role in the urea cycle, where it combines with carbamoyl phosphate to form citrulline during the breakdown of nitrogen in the body
2. A non-proteinogenic amino acid that functions in the metabolic pathway converting ammonia to urea, serving as an intermediate compound in nitrogen metabolism
3. An amino acid compound essential to the urea cycle that combines with other molecules to help the body eliminate excess nitrogen through urea synthesis

Etymology: Ornithine was named for the place its chemistry was first found: bird droppings. In 1877, the German chemist Max Jaffe isolated a benzoate ester from chicken excrement, and the compound he uncovered was given a name built from the Greek for "bird," "ornis" (genitive "ornithos"), and the -ine ending used for many nitrogen-containing compounds. The name is a blend of "ornith-" and the start of "urine," reflecting that the substance came from the waste of birds. The word therefore records a laboratory discovery rather than an ancient term. Its root, "ornith-," is the same Greek stem found in words like "ornithology," the scientific study of birds, so the chemical is named by analogy with the bird-related vocabulary that European scientists drew on in the nineteenth century.

Synonyms: amino acid