Respiration-driven proton translocation in Escherichia coli (Short Communication)

Abstract

Measurements were made of the stoicheiometry of respiration-driven proton translocation coupled to the oxidation of NAD(P)-linked or flavin-linked substrates in intact cells of Escherichia coli. Observed stoicheiometries (-->H(+)/O quotient; Mitchell, 1966) were approx. 4 with l-malate as substrate and approx. 2 for succinate, d-lactate and glycerol oxidation. It is concluded that the potential number of equivalent energy-conservation sites associated with the respiratory chain is 2 in aerobically grown cells of E. coli harvested during the exponential phase of growth.

Cytochrome o (bo) is a proton pump in Paracoccus denitrificans and Escherichia coli

“…A previous study of cytochrome o in E. coli ceils did not report proton pumping [24]. However, the H+/e -ratio for succinate oxidation was significantly above unity, without correction for proton backflux.…”

Alkaline Growth pH-Dependent Increase of Respiratory and NADH-Oxidation Activities of the Facultatively Alkaliphilic StrainBacillus lentusC-125

“…15) The respiratory rates of B. lent us C-l25 growing at alkaline pH that is near the upper pH limit for growth of the organism (Fig. 2) are 2.2-to 2.6-fold as fast as rates (1.0 Ilmol 0 atom/min/mg cell protein) reported for absolute alkaliphiles, B. alcalophilus and B. firmus RAB.…”

A metabolic study of Buchnera, the intracellular bacterial symbionts of the pea aphid Acyrthosiphon pisum

“…Firstly it is very likely that the bacteria respire aerobically in the symbiosis. This is suggested by sustained oxygen consumption of isolated preparations, at rates comparable to the respiration rate of Escherichia coli (Lawford & Haddock, 1973); and by the particularly rich supply of tracheae (structures which deliver oxygen to insect cells) to mycetocytes (C. N. Brough, personal communication). The second issue concerns the supply of nutrients from the insect mycetocyte cytoplasm to Buchnera.…”