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