Glutamine introducing

The tertiary structure of glutamate racemase has already been resolved and it has also been shown that a substrate analog glutamine binds between two cysteine residues. These data enabled us to predict that the new proton-donating amino acid residue should be introduced at position 74 instead of Gly for the inversion of enantioselectivity of the decarboxylation reaction. 

An extreme example of additional constraints introduced by the enzymatic mechanism of a biochemical reaction is the NAD synthase (glutamine-hydrolyzing) reaction (EC 6.3.5.1) (Alberty, 1994b) ... 

Recently Midelfort and Rose (4) introduced a positional isotope exchange technique that is also suitable for study by the chemical shift technique. Briefly, this technique follows the exchange of label from one part of a substrate to another due to rotational equivalence of some intermediate. The method was first applied to glutamine synthetase in the reaction ... 

Various numbering methods have been used to indicate substitution or other modification in or of the residues of a peptide. The method now recommended by lUPAC and introduced into the Dictionary of Natural Products (see Section 1.2.1) uses numerical locants of the type 3, where 3 is the locant of the substituent in the amino acid residue and 2 is the amino acid position in the ring or chain, numbered from the N-terminal end, which is standard for all peptides). A/ -methyloxytocin would indicate a methyl substituent on N-5 of the glutamine residue at position 4 of oxytocin. 

In writing out the conservation matrix for this biochemical reaction, the reactants are arbitrarily taken in the order glutamate, atp, pi, ammonia, glutamine, and adp. The elements are taken in the order C, O, N, and P. These elements introduce the following constraints ... 

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