L-prolyl-[Skp1 protein] + 2-oxoglutarate + O2 = trans-4-hydroxy-L-prolyl-[Skp1 protein] + succinate + CO2
l-prolyl-[skp1 protein] + 2-oxoglutarate + o2 = trans-4-hydroxy-l-prolyl-[skp1 protein] + succinate + co2