The mannitol cycle in Pleurotus ostreatus (Florida)

Abstract

In mushroom, presence of the mannitol cycle has not been reported so far although the polyol is supposed to be generated by the reduction of fructose by mannitol dehydrogenase. This study submits evidence for the presence of the mannitol cycle in Pleurotus ostreatus. The key enzyme of the cycle, mannitol‐1‐phosphate dehydrogenase (M1PDH), was present appreciably in all the developmental stages of the mushroom. However, the enzyme level dropped significantly at the onset of sporulation. The presence of M1DPH was confirmed by isozyme analysis and RT‐PCR mediated amplification of a ∼400 bp DNA fragment.

Initial Proteomic Identification of Secreted Proteins of White-Rot Fungus Porodaedalea pini Grown on Liquid Medium

“…This enzyme was also identified in Heterobasidiomycetes Cryptococcus neoformans [22]. Mannitol-1-phosphate 5-dehydrogenase is a key enzyme in the mannitol cycle, which is commonly found in white-rot basidiomycetes such as Phanerochaete crysosporium and Pleurotus ostreatus [23,24]. In this cycle, fructose-6-phosphate produced in the glycolytic pathway is converted to mannitol-1-phosphate by this enzyme, which is further dephosphorylated to mannitol [23,24].…”

“…Mannitol-1-phosphate 5-dehydrogenase is a key enzyme in the mannitol cycle, which is commonly found in white-rot basidiomycetes such as Phanerochaete crysosporium and Pleurotus ostreatus [23,24]. In this cycle, fructose-6-phosphate produced in the glycolytic pathway is converted to mannitol-1-phosphate by this enzyme, which is further dephosphorylated to mannitol [23,24]. Xylulose kinase plays an important role in xylose metabolism, which has also been identified in many fungi such as Saccharomyces cerevisiae [25].…”