Enables guanidinoacetate N-methyltransferase activity and identical protein binding activity. Involved in S-adenosylmethionine metabolic process; carboxylic acid metabolic process; and embryonic liver development. Predicted to be active in cytoplasm and nucleus. Human ortholog(s) of this gene implicated in amino acid metabolic disorder and guanidinoacetate methyltransferase deficiency. Orthologous to human GAMT (guanidinoacetate N-methyltransferase). [provided by Alliance of Genome Resources, Apr 2022]