Definition

Noun: * An amino acid that is not a building block of proteins but plays a crucial role in the urea cycle, a metabolic process that converts toxic ammonia into urea for excretion from the body.

Usage

• ornithine is an uncountable noun used primarily in biochemical and medical contexts.
• It is often discussed in relation to metabolic pathways, liver function, and detoxification processes.

Examples

• The enzyme ornithine transcarbamylase is essential for the ornithine cycle.
• A deficiency in ornithine metabolism can lead to hyperammonemia.
• Ornithine is a central intermediate in the conversion of ammonia to urea.

Advanced Usage

• Ornithine Cycle: Also known as the urea cycle, it is the metabolic pathway where ornithine is a key carrier molecule.
• Ornithine Decarboxylase: An enzyme that converts ornithine into putrescine, initiating polyamine synthesis, which is important for cell growth.

Variants and Related Words

• L-ornithine: The specific, naturally occurring form (isomer) of ornithine involved in human biochemistry.

Synonyms

• There are no direct common synonyms for this specific biochemical compound. It may be described as a non-proteinogenic amino acid or a urea cycle intermediate.

Related Phrases/Compounds

• Ornithine transcarbamylase (OTC): A liver enzyme.
• Ornithine decarboxylase (ODC): An enzyme in polyamine synthesis.

Noun

1. an amino acid that does not occur in proteins but is important in the formation of urea