Mammalian urea-cycle nitrogen disposal
The mammalian urea cycle combines nitrogen from ammonia and aspartate with bicarbonate-derived carbon to form urea.
Key knowledge
The mammalian urea cycle combines nitrogen from ammonia and aspartate with bicarbonate-derived carbon to form urea. Carbamoyl phosphate and ornithine give citrulline, followed by argininosuccinate and arginine; arginine cleavage releases urea and regenerates ornithine. The pathway spans mitochondrial and cytosolic steps and consumes ATP equivalents.
Conditions and scope
- Net urea production is tissue-specific, principally hepatic; it is not a cycle completed in every cell.
- Other organisms can excrete ammonia or uric acid instead; ATP molecules and high-energy phosphate equivalents are different counts.
Sources · 1
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Read named intermediate cycle, two nitrogen sources, mitochondrial/cytosolic distinction and ATP→AMP step; corrected transcript's ambiguous ATP-equivalent shorthand.
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Entry details
Permanent link to this entry ↗- Record identity
- uni-bio-urea-cycle
- Revision
- core.1
- Structured reference record
- University core expansion