Chapter 23, Problem 11RE

Interpretation Introduction

Interpretation:

The reactions involving glutamate dehydrogenase and glutamine synthetase that produce glutamine from ammonia and $\text{α}$-ketoglutarate are to be drawn.

Concept introduction:

Glutamate dehydrogenase is an enzyme present in the mitochondria, which utilizes ${\text{NAD}}^{+}$ and ${\text{NADP}}^{+}$. ${\text{NADP}}^{+}$ is involved in the conversion of α-ketoglutarate and free ammonia to glutamate. The intermediate formed between ammonia and $\text{α}$-ketoglutarate is a Schiff base, which ensures the presence of alpha carbon atom in the stereochemistry of glutamate.

In the next step, the formed Schiff base is protonated via hydride transfer from NADPH to form glutamate. Glutamine synthetase enzyme is involved in the metabolism of nitrogen. It utilizes nitrogen of ammonia produced by nitrate reduction, amino acid degradation, and photorespiration by catalyzing the condensation of glutamate and ammonia in the presence of ATP to form glutamine, ADP, and phosphate.