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Atractyloside Inhibition of Adenine Nucleotide Translocation in Mitochondria from Hypocotyls of Vigna sinensis cv. Seridó
Author(s) -
LIMA M. SILVA,
DENSLOW N. D.,
MELO D. FERNANDES
Publication year - 1977
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1977.tb05556.x
Subject(s) - chromosomal translocation , mitochondrion , biochemistry , oxidative phosphorylation , vigna , adenosine , nucleotide , biology , hypocotyl , adenosine diphosphate , chemistry , botany , gene , platelet , platelet aggregation , immunology
The translocation of adenine nucleotides into mitochondria isolated from hypocotyls of Vigna sinensis (L.) Savi cv. Serido was examined as a function of oxidative phosphorylation. Mitochondria membrane integrity was assessed by respiratory control and ADP:O ratios. A kinetic analysis of the translocation of adenosine diphosphate into the mitochondria revealed that the mechanism of translocation obeys classical Michaclis‐Menten kinetics with a Km of 25 μM for adenosine diphosphate. At moderate ratios of atraetyloside to adenosine diphosphate (lower than 0.03), atractyloside appears to be a competitive inhibitor of the translocation process, with a Ki of 0.4 μM. However, non‐linear kinetic parameters are observed with ratios higher than 0.06. A concentration of 2.5 μM atractyloside is sufficient to reduce the translocation of 100 μm ADP by 50%. This represents a higher level of sensitivity to atractyloside than reported for other plants.