Question

Which among the following represents the process of reductive deamination?

• A. ketoglutaric acid + NH4 + NADPH2 $\alpha \rightarrow$ Glutamic acid + H2O + ADP
• B. Glutamic acid + Oxaloacetic acid $\rightarrow$ a - ketoglutaric acid + Aspartic acid
• C. Glutamic acid + NH4 + ATP $\rightarrow$ a - Glutamine + ADP
• D. Aspartic acid + NH4 a - Asparagine + ADP

Hint:

Always look for the key reactants and products: $\alpha$-ketoglutaric acid + Ammonia forming Glutamic acid is the signature of reductive amination. Do not let minor typographical errors in exam options distract you from the main biochemical pathway.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
The question asks for the reaction representing "reductive deamination", which is a widely recognized typographical error in exam papers meant for "reductive amination".
Reductive amination is the process where ammonia reacts with an $\alpha$-keto acid to form an amino acid.

Step 2: Key Formula or Approach:
Identify the general biochemical equation for reductive amination: $\alpha$-ketoglutaric acid + NH$_4^+$ + NAD(P)H $\rightarrow$ Glutamate + H$_2$O + NAD(P)$^+$.

Step 3: Detailed Explanation:
In the reductive amination process, ammonia (represented as NH$_4$) reacts with $\alpha$-ketoglutaric acid in the presence of a reducing agent like NADPH$_2$.
This specific reaction forms glutamic acid and water.
Option (A) is the only option structurally depicting this amination process. Despite the misprint of "ADP" instead of NADP$^+$, and the misplaced "$\alpha$" symbol in the printed option, it accurately identifies the core reactants and products.
Option (B) represents transamination.
Options (C) and (D) represent amidation (formation of glutamine and asparagine).

Step 4: Final Answer:
Option (A) is the closest representation of the intended reductive amination reaction.