4'-O-methylisorhapontigenin + S-adenosyl-L-homocysteine + H(+) => isorhapontigenin + S-adenosyl-L-methionine
4'-o-methylisorhapontigenin + s-adenosyl-l-homocysteine + h(+) => isorhapontigenin + s-adenosyl-l-methionine
4'-O-methylisorhapontigenin + S-adenosyl-L-homocysteine + H(+) => isorhapontigenin + S-adenosyl-L-methionine
4'-o-methylisorhapontigenin + s-adenosyl-l-homocysteine + h(+) => isorhapontigenin + s-adenosyl-l-methionine