L-seryl-[protein] + UTP = O-(5'-uridylyl)-L-seryl-[protein] + diphosphate
l-seryl-[protein] + utp = o-(5'-uridylyl)-l-seryl-[protein] + diphosphate
L-seryl-[protein] + UTP = O-(5'-uridylyl)-L-seryl-[protein] + diphosphate
l-seryl-[protein] + utp = o-(5'-uridylyl)-l-seryl-[protein] + diphosphate