glutamine-fructose-6-phosphate transaminase (isomerizing) activity

Definition

Target type: molecularfunction

Catalysis of the reaction: beta-D-fructose 6-phosphate + L-glutamine = D-glucosamine 6-phosphate + L-glutamate. [EC:2.6.1.16, RHEA:13237]

Glutamine-fructose-6-phosphate transaminase (isomerizing) activity catalyzes the reversible transfer of an amino group from glutamine to fructose-6-phosphate, producing 6-phospho-D-gluconate and glutamate. This reaction involves two distinct steps:

1. **Transamination:** The enzyme first transfers the amino group from glutamine to the keto group of fructose-6-phosphate, forming an unstable imine intermediate. Glutamine is converted to glutamate in this process.
2. **Isomerization:** The imine intermediate then undergoes an isomerization reaction, resulting in the formation of 6-phospho-D-gluconate. This isomerization involves a shift of the carbonyl group and a change in the stereochemistry of the molecule.

The glutamine-fructose-6-phosphate transaminase (isomerizing) activity is a key enzyme in the gluconeogenic pathway, which is responsible for the synthesis of glucose from non-carbohydrate sources. By converting fructose-6-phosphate to 6-phospho-D-gluconate, this enzyme provides a precursor for the pentose phosphate pathway, which is crucial for the production of NADPH and essential biosynthetic intermediates.

Additionally, this activity has been implicated in other metabolic processes, including amino acid metabolism and the regulation of cellular redox state.'
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Proteins (2)

Compounds (2)