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040 _aMSU
_bEnglish
_cMSU
_erda
050 0 0 _aQK711.2 JOU
100 1 _aEprintsev, Alexander T
_eauthor
245 1 0 _aExpression and properties of the mitochondrial and cytosolic forms of aconitase in maize scutellum
_ccreated by Alexander T Eprintsev, Dmitry N Fedorin, Marina V Nikitina and, Abir U Igamberdiev
264 1 _aAmsterdam:
_bElsevier GmbH,
_c2015.
336 _2rdacontent
_atext
_btxt
337 _2rdamedia
_aunmediated
_bn
338 _2rdacarrier
_avolume
_bnc
440 _aJournal of palnt physiology
_vVolume 181
520 3 _aAconitase (EC 4.2.1.3) catalyzes the reversible interconversion of citrate, cis-aconitate, and D-isocitrate. It operates in mitochondria and cytosol. We investigated the expression of two aconitase genes (Aco1 and Aco4) and activities of the mitochondrial and cytosolic forms in maize (Zea mays L.) scutellum during germination. Both forms were isolated and purified. The cytosolic form had a higher pH optimum (8.0), twice higher affinity to citrate (K(m) 9.5 mM), and slightly lower affinity to D,L-isocitrate (K(m) 1.7 mM) as compared to the mitochondrial form (optimum pH 7.5, K(m) with citrate 21 mM, and K(m) with isocitrate 1.5 mM). The highest activity of both forms of aconitase was observed on the 4th day of germination; then the activity and expression of the cytosolic form sharply decreased, while the mitochondrial form decreased more slowly. The mitochondrial aconitase was more strongly inhibited by H2O2 (half-inhibition at 35 μM) than the cytosolic form (60 μM). Aconitase activity was not detected in the glyoxysomal fraction beyond the cross-contamination level. It is suggested that the mitochondrial form operates in the tricarboxylic acid cycle, whereas the cytosolic form participates in the reactions of the glyoxylate cycle taking place outside the glyoxysome.
650 _aAconitase
650 _aGlyoxylate cycle
650 _aMitochondria
700 1 _aFedorin, Dmitry N
_eco-author
700 1 _aNikitina, Marina V
_eco-author
700 1 _aIgamberdiev, Abir U
_eco-author
856 _uhttps://doi.org/10.1016/j.jplph.2015.03.012
942 _2lcc
_cJA
999 _c169207
_d169207