apigenin + S-adenosyl-L-methionine = acacetin + S-adenosyl-L-homocysteine + H(+)
apigenin + s-adenosyl-l-methionine = acacetin + s-adenosyl-l-homocysteine + h(+)
"apigenin 4'-O-methyltransferase"
"apigenin 4'-o-methyltransferase"