... apolar side chain of F331. Thus, the increment in the pKa of E399, in addition to it being closer to E187, mayhave resulted in a large shift in the pKa of E187. Changes in the dielectric constant ... mMBicine buffer 7.0–8.5). The pH stability of Sfbgly50 was checked by incubation in the same buffers for a time equal to the assay time and thendetermining the activity remaining at the optimum ... [10,12].Nevertheless, it is not possible to assume that the same isoccurring in the mutant R97M, because there is no data on the interactions between the substrate and the arginineresidue.Finally, another...