Glutamate amidation

Ribosylamine-5-phosphate pyrophosphate phospho-ribosyltransferase (glutamate-amidating) Phosphoribosyl pyrophosphate amidotransferase... 

Equation 1 has AG° = +14 kJ and is endergonic The mam reason for this is that one of the very stable carboxylate groups of glutamic acid is converted to a less stable amide function... 

FIGURE 18.35 Formation of THF from folic acid by the dihydrofolate reductase reaction. The R group on these folate molecules symbolizes the one to seven (or more) glutamate units that folates characteristically contain. All of these glutamates are bound in y-carboxyl amide linkages (as in the folic acid structure shown in the box A Deeper Look Folic Acid, Pterins, and Insect VFingis). The one-carbon units carried by THF are bound at N, or at or as a single carbon attached to both... 

Figure 11a shows a force-distance profile measnred for poly(L-glutamic acid) brushes (2C18PLGA(44)) in water (pH = 3.0, 10 M HNO3) deposited at 40 mN/m from the water subphase at pH = 3.0. The majority of peptides are in the forms of an a-helix (38% determined from the amide I band) and a random coil. Two major regions are clearly seen in... 

In the cell-wall antigen from Staphylococcus aureus M, taurine is linked as an amide (51) to a 2-acetamido-2-deoxy-D-galactosyluronic residue. l-Threonine and L-glutamic acid are linked as amides to D-glucuronic acid residues in the LPS from Rhodopseudomonas sphaeroides ATCC 17023 and in the capsular polysaccharide from Klebsiella K82, respectively. In the capsular polysaccharide from E. coli K54, L-serine and L-threonine, in the ratio 1 9, are linked to the carboxyl group of a D-glucuronic acid residue. In the capsular polysaccharide from Haemophilus influenzae type d,... 

Figure 29-8. The glutaminase reaction proceeds essentially irreversibly in the direction of glutamate and NH/ formation. Note that the amide nitrogen, not the a-amino nitrogen, is removed.

Use of the relatively small cyclopropane ring drastically reduces the potential for deleterious steric bulk effects and adds only a relatively small lipophilic increment to the partition coefficient of the drug. One of the clever elements of the rolicyprine synthesis itself is the reaction of d,l tranylcypromine (67) with L-5-pyrrolidone-2-carboxylic acid (derived from glutamic acid) to form a highly crystalline diastereomeric salt, thereby effecting resolution. Addition of dicyclohexylcarbodiimide activates the carboxyl group to nucleophilic attack by the primary amine thus forming the amide rolicyprine (68). 

Vitamin Ba (pyridoxine, pyridoxal, pyridoxamine) like nicotinic acid is a pyridine derivative. Its phosphorylated form is the coenzyme in enzymes that decarboxylate amino acids, e.g., tyrosine, arginine, glycine, glutamic acid, and dihydroxyphenylalanine. Vitamin B participates as coenzyme in various transaminations. It also functions in the conversion of tryptophan to nicotinic acid and amide. It is generally concerned with protein metabolism, e.g., the vitamin B8 requirement is increased in rats during increased protein intake. Vitamin B6 is also involved in the formation of unsaturated fatty acids. 

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