The Formation of Glutamine

The formation of glutamine from glutamate (Eq. 24-16) also depends upon a coupled cleavage of ATP ... 

Write a stepwise mechanism for the formation of glutamine on y-glutamyl phosphate. 

The formation of asparagine from aspartate is chemically analogous to the formation of glutamine from glutamate. Both transformations are amidation reactions and both are driven by the hydrolysis of ATP. The actual reactions are different, however. In bacteria, the reaction for the asparagine synthesis is... 

Ammonium ions are also incorporated into cell metabolites by the formation of glutamine, the amide of glutamate ... 

At 25° C, AG° for this reaction is 0.06 kcal Suppose that pyruvate is further oxidized in a process for which AG° is 61.8 kcal. Does this enhance the formation of glutamine ... 

In muscle, glutamine synthetase is very active, catalyzing the formation of glutamine from glutamate and ammonia at the expense of a molecule of ATP. In the liver, the rate... 

The y-linkage was established by the formation of glutamine and N -isopropylglutamine, and the structure was confirmed by synthesis (202). 

Show the full mechanism for the formation of glutamine by reaction of glutamate 5-phosphate with ammonia, and compare that full mechanism to the abbreviated mechanism shown in Figure 20.12 to see the difference. 

Isotopic labeling has also been cleverly used to demonstrate the existence of enzyme-bound intermediates that do not readily dissociate into solution. The enzyme glutamine synthetase catalyzes the formation of glutamine from ATP and ammonia possibly through a tightly bound glutamyl phosphate intermediate. 

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