Glutamine, biosynthesis

Why did nature waste an ATP in glutamine biosynthesis The lone pair of electrons on an ammonia could have attacked the y-carbonyl group of a glutamate. Subsequent elimination of an oxide ion and release of a-proton from the nitrogen would produce a glutamine without the consumption of an ATP. 

Lydon, J., Duke, S.O. Inhibitors of glutamine biosynthesis. In Plant Amino Acids Biochemistry and Biotechnolgy, B.K. Singh, ed. Marcel Dekker, New York. 1999. pp. 445-464. 

Lydon, J. and Duke, S. O. 1998. Inhibitors of glutamine biosynthesis.In Sing, B.K. (Ed.). Plant Amino Acids Biochemistry and Biotechnology. 

Enzymes of Glutamate and Glutamine Biosynthesis in Bacillus licheniformis Robert W. Bemlohr, Harold J. 

Nevertheless the biosynthesis of glutamine proceeds from glutamic acid The dif ference is that the endergonic process m Equation 1 is coupled with the strongly exer gome hydrolysis of ATP... 

One example of a naturally occurring diazirine, duazomycin A (137 Scheme 11.20), has been reported, isolated in 1985 from a Streptomyces species during a screen for herbicidal compounds [196], It was fotind to inhibit de novo starch synthesis and it was suggested that this is due to direct inhibition of protein synthesis. Duazomycin A is structurally related to 6-diazo-5-oxo-L-norleucine (138), also reported as a natural product from Streptomyces [197], which acts as a glutamine antagonist and inhibits purine biosynthesis [198],... 

The enzymes glutamate dehydrogenase, glutamine synthetase, and aminotransferases occupy central positions in amino acid biosynthesis. The combined effect of... 

Condensation of CO2, ammonia, and ATP to form carbamoyl phosphate is catalyzed by mitochondrial carbamoyl phosphate synthase I (reaction 1, Figure 29-9). A cytosolic form of this enzyme, carbamoyl phosphate synthase II, uses glutamine rather than ammonia as the nitrogen donor and functions in pyrimidine biosynthesis (see Chapter 34). Carbamoyl phosphate synthase I, the rate-hmiting enzyme of the urea cycle, is active only in the presence of its allosteric activator JV-acetylglutamate, which enhances the affinity of the synthase for ATP. Formation of carbamoyl phosphate requires 2 mol of ATP, one of which serves as a phosphate donor. Conversion of the second ATP to AMP and pyrophosphate, coupled to the hydrolysis of pyrophosphate to orthophosphate, provides the driving... 

Antifolate Drugs or Glutamine Analogs Block Purine Nucleotide Biosynthesis... 

Since biosynthesis of IMP consumes glycine, glutamine, tetrahydrofolate derivatives, aspartate, and ATP, it is advantageous to regulate purine biosynthesis. The major determinant of the rate of de novo purine nucleotide biosynthesis is the concentration of PRPP, whose pool size depends on its rates of synthesis, utilization, and degradation. The rate of PRPP synthesis depends on the availabihty of ribose 5-phosphate and on the activity of PRPP synthase, an enzyme sensitive to feedback inhibition by AMP, ADP, GMP, and GDP. 

Several reactions of IMP biosynthesis require folate derivatives and glutamine. Consequently, antifolate drugs and glutamine analogs inhibit purine biosynthesis. 

Waagepetersen, H. S., Sonnewald, U., Larsson, O. M. etal. Multiple compartments with different metabolic characteristics are involved in biosynthesis of intracellular and released glutamine and citrate in astrocytes. Glia 35 246-252, 2001. 

L. J. Reitzer, Ammonia Assimilation and the Biosynthesis of Glutamine, Glutamate, Aspartate, Asparagine, L-alanine, and D-alanine. In Escherichia coll and Salmonella, Cellular and Molecular Biology F. C. Neidhardt, Ed. ASM Press Washington, DC, 1996 Vol. 1, pp 391 07. 

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