MMUT and Parkinson disease: Compared with that of the control group, the gut microbiome of 6-OHDA-induced PD mice exhibited a significantly decreased potential to produce propionate, as evidenced by the decreased RA of K01847 (methylmalonyl-CoA mutase, Mut; 6-OHDA vs control: p = 0.0325) (Fig. 5a, Supplemental Table S6).