Fig. 9

Putative metabolic pathway involved in d-fructose accumulation and inhibition of biosynthesis of glycerol-3-phosphate (G3P) and d-mannitol under Zn²⁺ deficient condition. In this pathway, insufficient supply of Zn²⁺ can inhibit fructose-bisphosphate aldolase and NADPH (reduced form of NADP: nicotinamide adenine dinucleotide phosphate) dehydrogenase as it is a cofactor of both enzymes. The inhibition of the former enzyme causes smaller amount of G3P content, and that of the latter one results in d-fructose accumulation and inhibition of d-mannitol biosynthesis as insufficient Zn²⁺ can inhibits NADPH dehydrogenase, which leads insufficient supply of NADP, a cofactor of mannitol dehydrogenase