Enables protein-lysine N-methyltransferase activity. Involved in peptidyl-lysine trimethylation; positive regulation of sensory perception of pain; and regulation of proton transport. Predicted to be located in mitochondrial crista. Predicted to be active in mitochondrion. Orthologous to human ATPSCKMT (ATP synthase c subunit lysine N-methyltransferase). [provided by Alliance of Genome Resources, Apr 2022]