PubMed Health⌕ Search

Biomedical subjects

W J Ingledew

Publications and source records attributed to W J Ingledew.

68 records · Page 4Linked to original sources
PubMed1977

EPR studies of higher plant mitochondria. I Ubisemiquinone and its relation to alternative respiratory oxidations.

An EPR investigation of the region of the higher plant respiratory chain involving ubiquinone and Center S-3 of succinate dehydrogenase is reported. At temperatures close to those of liquid helium, first derivative spectra corresponding to Center S-3 (gmax = 2.017) and a signal split around g = 2.00 (major features of peaks and troughs at g values of 2.045, 2.03, 1.985, 1.97 and 1.96) were observed in mung bean (Phaseolus aureus), Arum maculatum spadix, Sauromatum guttatum spadix and tulip bulb (Tulipa gesnerana) mitochondria. The split signal was small or absent in potato tuber and Symplocarpus foetidus spadix mitochondria. The redox behavior of these signals in mung bean mitochondria in a variety of respiratory steady-state conditions suggested that the components giving rise to them were an integral part of the respiratory chain and were located on the substrate side of coupling Site II. The split signal could be removed by addition of hydroxamic acids in all tissues tested, although the Ks of this effect was an order of magnitude higher than the Ki of inhibition of the alternative respiratory pathway in mung bean and Sauromatum guttatum spadix mitochondria. The results are discussed in relation to the current ideas on the ordering of components in the region around the classical Site II of the respiratory chain and in relation to the location of the alternative respiratory oxidase pathway of higher plants.

Cyanides↗
PubMed1977

The probable site of action of thenolytrifluoracetone on the respiratory chain.

1. It is shown that the electron-transfer inhibitor thenoyltrifluoroacetone abolishes a respiratory-chain electron-paramagnetic-resonance absorbance due to spin-spin interactions of ubisemiquinones at concentrations similar to those required for inhibition of succinate oxidation. 2. A specific site of interaction of thenoyltrifluoroacetone with the respiratory chain is proposed to be on the ubisemiquinone with which succinate dehydrogenase reacts. 3. Our results further demonstrate the close association of the HiPIP (high-potential iron-sulphur) centre of succinate dehydrogenase with ubisemiquinone.

Animals↗
PubMed1976

Resolution and functional characterization of two mitochondrial iron-sulphur centres of the 'high-potential iron-sulphur protein' type.

Two distinct iron-sulphur centres of the 'HiPIP' (high-potential iron-protein) type are distinguished in both pigeon heart and ox heart mitochondria. These two species, although both are paramagnetic in the oxidized state, exhibit signals which differ in their detailed line shape, field position, and temperature- and power-dependence. They also exhibit different thermodynamic and kinetic behaviour and are located on opposite sides of the mitochondrial coupling membrane. One of these centres corresponds to Centre S-3. The other 'HiPIP'-type centre is removed readily from the mitochondrial membrane and its physiological function is not known.

Animals↗