Figure 4. Effect of PGO on arginine variants of LdAdK.

Unmodified activity of each enzyme was considered to be 100% (white bars). PGO (15 mM) for 30 min was used for modification (black bars) and 0.3 mM Ado was used for the substrate-protection experiment (grey bars). Actual specific activities of R131A, R69K and R69A are 5.3, 3.6 and 3.2% of wild-type respectively. Similar experiments could not be performed with the R69K/R131A double mutant because its activity is too low for this kind of inhibition studies.