FIG 5.

Analysis of the phosphoribohydrolase activity of SiRe_0427 mutants on AMP. (A) The catalytic and substrate binding mutants lost their phosphoribohydrolase activity on AMP. The reaction was performed at 65°C and pH 7.4 for 4 h (see Materials and Methods). One to two microliters from the mixture was then dotted onto a TLC sheet. After separation, the plate was dried and visualized by UV illumination at 254 nm. (B) Quantification of the results in panel A. The AMP and adenine standards are on the left side of the figure. The reaction times (hours) are indicated at the bottom of the figure. All experiments were repeated at least three times.