a N-(2-hydroxyacyl)sphing-4-enine + UDP-alpha-D-galactose <=> a 1-(beta-D-galactosyl)-2-(2-hydroxyacyl)sphing-4-enine + UDP + H(+)
a n-(2-hydroxyacyl)sphing-4-enine + udp-alpha-d-galactose <=> a 1-(beta-d-galactosyl)-2-(2-hydroxyacyl)sphing-4-enine + udp + h(+)