Table 1. Time-dependent changes in CD signal in absence or presence of 10- or 50-fold molar excess of SAM.

Residual CD signal remaining after 8 hours measurementsa (%)
Protein variant	−SAM	+SAM10-fold	+SAM50-fold
TPMTwt	85	97***	105***
TPMT p.Y240C	75	80	90***
TPMT p. Y240S	77	77	75

CD signal monitored at 222 nm. ^***Significant level of one-way ANOVA: p ≤ 0.001.

^aThe percentage of CD signal remaining after 8 hours of measurements at 37 °C.