Abstract:The finding of dissimilatory nitrate reductase in fungi breaks the traditional concept that denitrification has been considered to only occur in a prokaryotic cell. Dissimilatory nitrate reduction in fungi includes denitrification and ammonia fermentation, which occurs under the conditions of limited aeration. Nitrate and nitrite can induce denitrification-related enzymes, which include nitrate reductase, nitrite reductase and nitric oxide reductase. Nitrate reductase and nitrite reductase exists in mitochondria, and enzymatic reactions they catalyze are coupled with ATP generation through ATP synthase in the respiratory chain and produce nitric oxide(NO). In contrast to the two enzymes, NO reductase uses NADH as the direct electron donor and thus might function in the regeneration of NAD+ and detoxification of the toxic radical, NO. Ammonia fermentation can reduce nitrate to ammonium and couples acetogenic reaction with substrate-level phosphorylation. In this review, the latest progress about the involved main enzymes, their gene expression regulation, and the comparison of the dissimilatory nitrate reduction between fungi and bacteria were discussed.
