SET domain-containing proteins, such as SMYD2, catalyze lysine methylation.Protein-lysine N-methyltransferase that methylates both histones and non-histone proteins. Specifically methylates histone H3 'Lys-4' (H3K4me) and dimethylates histone H3 'Lys-36' (H3K36me2). Has also methyltransferase activity toward non-histone proteins.