“…Precursor-feeding experiments firmly established the intermediacies of 2-epi-5-epivaliolone, 5-epi-valiolone, valienone, and validone in validamycin biosynthetic pathways and substantiated that no phosphorylated intermediate is involved (Dong et al, 2001). However, the product of vldC is homologous to 2-epi-5-epi-valiolone 7-kinase in the acarbose pathway, implying there is a phosphorylated intermediate in the validamycin m-C 7 N cyclitol pathway (Singh et al, 2006;Zhang et al, 2002). Later, VldC was characterized as glucokinase, contradicting the involvement of a phosphorylated intermediate in the validamycin m-C 7 N cyclitol biosynthesis (Seo et al, 2006).…”