label: [(1->4)-alpha-D-galacturonosyl](n) + UDP-alpha-D-galacturonate = [(1->4)-alpha-D-galacturonosyl](n+1) + UDP + H(+)
label_lc: [(1->4)-alpha-d-galacturonosyl](n) + udp-alpha-d-galacturonate = [(1->4)-alpha-d-galacturonosyl](n+1) + udp + h(+)