N-terminal L-alanyl-L-prolyl-L-lysyl-[protein] + S-adenosyl-L-methionine <=> N-terminal N-methyl-L-alanyl-L-prolyl-L-lysyl-[protein] + S-adenosyl-L-homocysteine + H(+)
n-terminal l-alanyl-l-prolyl-l-lysyl-[protein] + s-adenosyl-l-methionine <=> n-terminal n-methyl-l-alanyl-l-prolyl-l-lysyl-[protein] + s-adenosyl-l-homocysteine + h(+)