... of blue dextran. (X) Protein standards; (A) BLXI. Linear regression (1),with an r2 of 0.951, is based on the elution data of all four proteinstandards. Linear regression (2), with an r2 of ... r2 of 0.981, is based on theelution data of the 200, 150, and 66 kDa protein standards. Linear regressions (1) and (2) give molecular masses of 200 and 177.5 kDa,respectively, for BLXI.6294 ... glucose. BLXI activity in the presence of Mn2þ and Mg2þreached only 6% and 15%, respectively, of the activityin the presence of Co2þ(Fig. 4A). Co2þ,Mn2þ, and Mg2þactivation constants for...