Enables methylmalonyl-CoA mutase activity. Acts upstream of or within post-embryonic development. Located in mitochondrion. Is expressed in several structures, including alimentary system; genitourinary system; lung; nervous system; and trophectoderm. Used to study methylmalonic aciduria due to methylmalonyl-CoA mutase deficiency. Human ortholog(s) of this gene implicated in methylmalonic aciduria due to methylmalonyl-CoA mutase deficiency. Orthologous to human MMUT (methylmalonyl-CoA mutase). [provided by Alliance of Genome Resources, Apr 2022]