Enables betaine-homocysteine S-methyltransferase activity. Acts upstream of or within methionine biosynthetic process. Predicted to be located in cytosol and extracellular exosome. Predicted to be part of protein-containing complex. Is expressed in several structures, including brain ventricle and choroid plexus; early conceptus; gonad; liver; and prostate gland. Orthologous to human BHMT (betaine--homocysteine S-methyltransferase). [provided by Alliance of Genome Resources, Apr 2022]