label: glucuronoxylan D-glucuronate + n S-adenosyl-L-methionine = glucuronoxylan 4-O-methyl-D-glucuronate + n S-adenosyl-L-homocysteine + n H(+)
label_lc: glucuronoxylan d-glucuronate + n s-adenosyl-l-methionine = glucuronoxylan 4-o-methyl-d-glucuronate + n s-adenosyl-l-homocysteine + n h(+)