label: N-terminal N,N,N-trimethyl-L-seryl-L-prolyl-L-lysyl-[protein] + S-adenosyl-L-homocysteine + H(+) => N-terminal N,N-dimethyl-L-seryl-L-prolyl-L-lysyl-[protein] + S-adenosyl-L-methionine
label_lc: n-terminal n,n,n-trimethyl-l-seryl-l-prolyl-l-lysyl-[protein] + s-adenosyl-l-homocysteine + h(+) => n-terminal n,n-dimethyl-l-seryl-l-prolyl-l-lysyl-[protein] + s-adenosyl-l-methionine