... ap-cation -binding < /b> site, and an acyl -binding < /b> pocket) are the same in AChE and BuChE (Fig. 1). The acyl -binding< /b> pocket, which is responsible for the difference in substratespecificity between the two ... spontaneousreduction of DTNB from blank samples. The observedrate, in terms of mol productÆmin)1ÆL)1, was obtained by< /b> dividing the DA420Æmin)1 by < /b> the absorption coefficient for the 5-thio-2-nitrobenzoic ... substrate inhibition most probably reflects a pH-dependent difference in the response of the protein to excess-substrate binding.< /b> That isto say, the structure of the BuChE active site changes in response...