Glycerol metabolism in superoxide dismutase-deficientEscherichia coli

Abstract

Escherichia coli, which lacks cytoplasmic superoxide dismutases, exhibits various phenotypic deficits if grown aerobically. Here we report that sodAsodB E. coli cannot use glycerol under aerobic conditions. The reason is low activity of glycerol kinase (GK), the rate-limiting enzyme in glycerol metabolism. Superoxide does not inactivate GK, but makes it susceptible to inactivation by a heat-labile factor present in the cell-free extracts. This factor seems to be part of a proteolytic system, which recognizes and degrades oxidatively modified proteins.

Manganese SOD Mimics Are Effective Against Heat Stress in a Mutant Fission Yeast Deficient in Mitochondrial Superoxide Dismutase

“…Other possible explanations of manganese SOD mimics efficiency in heat stress involves the metabolism of glycerol [9,18] or trehalose [19], suggesting that the heat stress adaptation and protection is a complex process which still needs to be cleared.…”

Probing the adaptive response of Escherichia coli to extracellular Zn(II)

“…All of these proteins are also involved in various metabolic processes, and no link to Zn(II) has been reported for any of them. Mn-containing superoxide dismutase (Mn) (SodA) has been reported to regulate glycerol metabolism by controlling the activity of glycerol kinase (Benov & Al-Ibraheem 2001) in addition to its role in the detoxification of reactive oxygen species (O 2 ) ) (Hopkin et al 1992). Outer membrane protein X (OmpX), which was reported to be induced either by low and high pH (Stancik et al 2002), is involved in cell-surface interactions, and its homologs in other organisms have been implicated in bacterial virulence (Mecsas et al 1995).…”