Estimation of the molecular weight of native Rv0535. Purified Rv0535 was applied to a Superdex 200 PG size exclusion column, and MTA cleavage activity was measured in fractions eluting from the column. The fraction with the most activity was used to calculate Kav according to the following equation: Kav=(Ve−Vo)/(Vc−Vo), where Vo is the column void volume, Ve is the elution volume, and Vc is the geometric column volume. Vo was determined based on the Ve of Blue Dextran 2000. MW, molecular weight.