Correct option is C
α-Ketoglutarate is a key intermediate in the citric acid (Krebs) cycle and plays a vital role in nitrogen metabolism, particularly in the transamination reactions involved in amino acid catabolism. In these reactions, an amino group from an amino acid is transferred to α-ketoglutarate, converting it into glutamate, while the amino acid itself becomes a corresponding keto acid. This process is catalyzed by transaminase (aminotransferase) enzymes. Therefore, α-ketoglutarate acts as the primary amino group acceptor during amino acid catabolism in most cells.
This transformation is essential for nitrogen balance in the body and for funneling amino groups into pathways like the urea cycle or further amino acid synthesis.
Additional Information:
- (a) Fumarate: This is an intermediate in the citric acid cycle and urea cycle but does not act as a primary acceptor of amino groups. It participates in amino acid metabolism indirectly.
- (b) Glutamine: This compound is a product of amino group donation, not an acceptor. It carries two amino groups and serves as a nitrogen transporter in the body.
- (d) Asparagine: Like glutamine, asparagine contains an amino group, but it is not a typical acceptor in transamination. Instead, it is synthesized via the transfer of an amino group to aspartate.
