L-seryl-[protein] + butanoyl-CoA = O-butanoyl-L-seryl-[protein] + CoA
l-seryl-[protein] + butanoyl-coa = o-butanoyl-l-seryl-[protein] + coa
L-seryl-[protein] + butanoyl-CoA = O-butanoyl-L-seryl-[protein] + CoA
l-seryl-[protein] + butanoyl-coa = o-butanoyl-l-seryl-[protein] + coa