Cyanide‐resistant respiration: A non‐phosphorylating electron transport pathway acting as an energy overflow

Alterations in Growth, Photosynthesis, and Respiration in a Starchless Mutant of Arabidopsis thaliana (L.) Deficient in Chloroplast Phosphoglucomutase Activity

“…Because the starchless mutant accumulates high levels of soluble carbohydrate in the light which rapidly decline in the dark, it seems likely that, as suggested (2,3,6), the amount of respiration is proportional to the availability of substrate rather than to the demand for ATP and NADH. It remains to be seen if the abnormally high respiration of the mutant is due to alternative oxidase activity which has been invoked to explain substrate-regulation of respiration (3,15,29). This concept is of particular interest because of the possibility that crop productivity might be amplified by control of nonproductive respiratory losses (9).…”

“…The implication is that the amount of respiration is regulated by substrate supply rather than demand for ATP or reducing equivalents. Indeed, it has been suggested that, under conditions of high carbohydrate supply, a substantial proportion of the reductant generated during carbohydrate catabolism may be consumed by the alternative oxidase without being linked to ATP production (3,15 …”

Molecular Distinction between Alternative Oxidase from Monocots and Dicots

“…Two roles among Aox isozymes may be proposed based on the available expression data summarized in Table I-one a constitutive isozyme required for a generic, "housekeeping" function in respiratory metabolism, and the other related to a particular need under stress conditions. This proposal encompasses the long-held hypothesis that AOX acts as an overflow for carbon metabolism to uncouple anaplerotic functions from ATP production (Lambers, 1982) and the more recent hypothesis that it functions to minimize reactive oxygen species production from electron transport during oxidative stress (Purvis and Shewfelt, 1993; Wagner and Moore, 1997).…”

Remodeled Respiration in ndufs4 with Low Phosphorylation Efficiency Suppresses Arabidopsis Germination and Growth and Alters Control of Metabolism at Night

“…These NAD(P)H dehydrogenases have been identified and localized either on the cytosolic or the matrix side of the inner membrane and transfer electrons from cytosolic or matrix NADH pools directly to ubiquinone (Rasmusson and Moller, 1991;Rasmusson et al 2008). In addition, the alternative oxidase (AOX) can bypass the cytochrome pathway by oxidizing ubiquinol and reducing molecular oxygen, and it does this in a nonphosphorylating manner (Lambers, 1982).…”