Enables protein-L-histidine N-pros-methyltransferase activity. Predicted to act upstream of or within methylation. Predicted to be located in mitochondrion. Predicted to be active in endoplasmic reticulum. Is expressed in retina inner nuclear layer and retina outer nuclear layer. Orthologous to human METTL9 (methyltransferase like 9). [provided by Alliance of Genome Resources, Apr 2022]