Characterisation and biosynthesis of d-erythroascorbic acid in Phycomyces blakesleeanus

• Published in: Fungal genetics and biology Vol. 42; no. 5; pp. 390 - 402
• Main Authors: Baroja-Mazo, Alberto, Valle, Pilar del, Rúa, Javier, de Cima, Sergio, Busto, Félix, de Arriaga, Dolores, Smirnoff, Nicholas
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-05-2005
• Subjects: 2,6-Dichloroindophenol - chemistry; alcohol oxidoreductases; antioxidant activity; Antioxidant defence; arabinose; Arabinose - metabolism; arabinose dehydrogenase; Ascomycetes; ascorbic acid; Ascorbic Acid - biosynthesis; Ascorbic Acid - chemistry; ascorbic acids; Basidiomycetes; biosynthesis; d-Arabinose dehydrogenase; d-Erythroascorbate biosynthesis; D-erythroascorbate glucoside; D-erythroascorbic acid; enzyme activity; Filamentous fungi; fucose; Fucose - metabolism; galactose; Galactose - metabolism; Glycosylation; microbial growth; Molecular Weight; Mycelium - chemistry; oxidation; Oxidation-Reduction; Oxidative stress; Phycomyces - enzymology; Phycomyces - metabolism; Phycomyces blakesleeanus; Spores - chemistry; Sugar Alcohol Dehydrogenases - chemistry; Sugar Alcohol Dehydrogenases - isolation & purification; Sugar Alcohol Dehydrogenases - metabolism; Zygomycetes; Oxidative stress; d-Arabinose dehydrogenase; Phycomyces blakesleeanus; d-Erythroascorbate biosynthesis; Filamentous fungi; Antioxidant defence
• ISSN: 1087-1845; 1096-0937
• DOI: 10.1016/j.fgb.2005.01.005

d-Erythroascorbate and
d-erythroascorbate glucoside have been identified in the Zygomycete fungus
Phycomyces blakesleeanus. Ascomycete and Basidiomycete fungi also synthesise
d-erythroascorbate instead of
l-ascorbate, suggesting that
d-erythroascorbate synthesis evolved in the common ancestor of the fungi. Both compounds accumulate in
P. blakesleeanus at higher levels than observed in other fungal species.
d-Erythroascorbate glucoside reduced dichlorophenolindophenol as effectively as
l-ascorbate, but was more stable to autoxidation.
d-Erythroascorbate glucoside predominated in spores and stationary phase mycelium. Free
d-erythroascorbate accumulated during the exponential phase of mycelial growth and decreased to very low levels in the stationary phase. This suggests an association between growth and free
d-erythroascorbate.
P. blakesleeanus converted exogenous
d-arabinose to
d-erythroascorbate and its glucoside. A monomeric NAD-dependent
d-arabinose dehydrogenase of 41
kDa was purified to near homogeneity. The enzyme oxidised
d-arabinose,
l-galactose, and
l-fucose. Correspondingly, mycelium converted exogenous
l-galactose and
l-fucose to
l-ascorbate and 6-deoxyascorbate, respectively. The antioxidant role of
d-erythroascorbate and its glucoside is discussed.