NTG degradation and GDN production by hALDH1a1 WT or mutants at 37°C. Black circle represents WT, white circle represents C302A. Solid lines represent NTG, dashed lines represent 1,2-GDN, and dotted lines represent 1,3-GDN. Data are expressed as mean ± SD, n = 3. (***p < 0.001 WT vs. C302A for NTG, 1,2-GDN, and 1,3-GDN)