Alanine cycle

From Citizendium
Jump to navigation Jump to search
This article is developing and not approved.
Main Article
Discussion
Related Articles  [?]
Bibliography  [?]
External Links  [?]
Citable Version  [?]
 
This editable Main Article is under development and subject to a disclaimer.
Alanine cycle.GIF

The alanine cycle is a way for muscle cells to use amino acids as energy sources, while transferring to the liver the expensive task of dealing with the ammonium released from those aminoacids.

Muscles contain transaminases which transfer the amino group from amino acids to pyruvate, yielding alanine and a α-ketoacid similar to the original amino acid. The α-ketoacid is further metabolized, yielding ATP. Alanine is transported though the bloodstream, where it is transaminated to pyruvate, which is converted through gluconeogenesis into glucose. The amino group released from alanine is taken up by α-ketoglutarate, converting it to glutamate. NH4+ is removed from glutamate by glutamate dehydrogenase, and incorporated in urea, which is excreted in urine.