label: 3-methylbutanoyl-CoA + S-adenosyl-L-methionine => N-isovaleryl-L-homoserine lactone + S-methyl-5'-thioadenosine + CoA + H(+)
label_lc: 3-methylbutanoyl-coa + s-adenosyl-l-methionine => n-isovaleryl-l-homoserine lactone + s-methyl-5'-thioadenosine + coa + h(+)