deaminated

Deaminated describes a molecule that has undergone deamination, the removal of an amino group (-NH2) from an organic compound. This chemical change often leaves behind a carbonyl or other functional group and releases ammonia or ammonium as a byproduct.

In metabolism, deamination is a central step in amino acid catabolism. Oxidative deamination, performed by enzymes such as glutamate dehydrogenase, converts amino acids into their corresponding alpha-keto acids while releasing free ammonia. Transamination transfers amino groups to another molecule, after which deamination finalizes nitrogen disposal, typically feeding the urea cycle in liver cells. These processes help manage nitrogen balance and provide carbon skeletons for energy production or biosynthesis.

In nucleic acids, deamination refers to the loss of an amino group from a base. Cytosine deaminates to uracil, a change that can lead to C:G to T:A mutations if unrepaired. Adenine can deaminate to hypoxanthine and guanine to xanthine; thymine is relatively resistant to deamination. Cells use base excision repair and related pathways to recognize and remove such damaged or mispaired bases, maintaining genetic stability. RNA editing also makes use of deaminase enzymes to alter bases in RNA, such as cytidine deaminases and adenosine deaminases, producing functional diversity in some contexts.

Spontaneous deamination can occur due to aging, heat, or chemical exposure, and is a consideration in food processing and biotechnological applications. In summary, deaminated describes molecules altered by loss of amino groups, with significant consequences for metabolism, genetics, and molecular biology.