Valine 44 and valine 45 of human glutathione synthetase are key for subunit stability and negative cooperativity.

ABSTRACT: It was hypothesized that residues Val44 and Val45 serve as important residues for human glutathione synthetase (hGS) function and stability given their location at the dimer interface of this enzyme. Computational studies suggest that mutation at Val45 has more impact on the structure and stability of hGS than does mutation at Val44. Experimentally, enzymes with mutations at the 44 and or 45 positions of hGS were prepared, purified and assayed for initial activity. Val45 position mutations (either to alanine or tryptophan) have a greater impact on enzyme activity than do mutations at Val44. Differential scanning calorimetry experiments reveal a loss of stability in all mutant enzymes, with V45 mutations being less stable than the corresponding Val44 mutations. The γ-GluABA substrate affini

SUBMITTER: Slavens KD 

PROVIDER: S-EPMC3165040 | biostudies-literature | 2011 Jul

REPOSITORIES: biostudies-literature