Extended Data Fig. 4: A summary of hypothetical intermediates and degradation products of the C9 acyl unit.
From: Complete biosynthesis of the potent vaccine adjuvant QS-21
6-Methyl-3,5-dioxooctanoyl-CoA (6) is reduced by a keto-reductase to produce either 5-hydroxy-6-methyl-3-oxooctanoyl-CoA or 3-hydroxy-6-methyl-5-oxooctanoyl-CoA. These intermediates are then further reduced to give 3,5-dihydroxy-6-methyloctanoyl-CoA. These CoA-derivatives are unstable and prone to spontaneous chemical degradation to give C9 δ-lactone (7), monoreduced C9-δ-lactone (a), monoreduced C9-δ-lactone (b), or fully reduced C9-δ-lactone (c), respectively. KR, keto-reductase.
