Open AccessAn Analysis of the Control of Phosphorylation-Coupled Respiration in Isolated Plant Mitochondria
Author(s) -
Anna Padovan,
Ian B. Dry,
Joseph T. Wiskich
Publication year - 1989
Publication title -
plant physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.554
H-Index - 312
eISSN - 1532-2548
pISSN - 0032-0889
DOI - 10.1104/pp.90.3.928
Subject(s) - respiration , mitochondrion , phosphorylation , cellular respiration , biochemistry , biology , chemistry , microbiology and biotechnology , botany
The control of phosphorylation-coupled respiration in isolated turnip (Brassica rapa) mitochondria was investigated according to the principles of metabolic control analysis as developed by H. Kacser and J. A. Burns ([1973] Symp Soc Exp Biol 32: 65-104) and R. Heinrich and T. A. Rapoport ([1974] Eur J Biochem 42: 97-105). Inhibitor titration studies were used to determine quantitatively the amount of control exerted by four individual processes-cytochrome bc(1), cytochrome oxidase, H(+)-ATPase, and the adenine nucleotide carrier-on respiratory flux under ADP-excess (state 3) and ADP-limited (state 4) conditions with a range of respiratory substrates. Under state 3 conditions control strength was found to be distributed between cytochrome oxidase, cytochrome bc(1), and H(+)-ATPase in decreasing order of importance. The adenine nucleotide carrier exerted no control on respiratory flux under these conditions. Control strength at each step was found to vary with different substrates and with the respiratory flux as altered by ADP supply, i.e. virtually zero control strength at cytochrome oxidase and cytochrome bc(1) under state 4 conditions.