Subcellular Location and Some Properties of Isocitrate Dehydrogenase Isozymes in<i>Euglena gracilis</i>

Oda, Yuji; Miyatake, Kazutaka; Nakano, Yoshihisa; Kitaoka, Shôzaburô

doi:10.1080/00021369.1981.10864934

Cited by 4 publications

(3 citation statements)

References 6 publications

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“…It has been reported that SSA dehydrogenase exists as two isoenzymes, one requiring NADP+ and the other NADI as electron acceptor, and that NADP+-linked SSA dehydrogenase is induced by L-glutamate, whereas the NAD+-linked enzyme is not [2]. When [11,12]. Euglena cells have high NADPH-dependent L-glutamate dehydrogenase activity when grown on L-glutamate, but the activity is repressed completely in cells grown on (NH4)2S04 as nitrogen source [13,14].…”

Section: Discussionmentioning

confidence: 99%

Effect of l-glutamate on 2-oxoglutarate decarboxylase in Euglena gracilis

Shigeoka

Hanaoka

Kishi

et al. 1992

Biochemical Journal

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The effect of tricarboxylic acid-cycle intermediates and related compounds on 2-oxoglutarate decarboxylase activity was investigated. The addition of L-glutamate to Euglena cells grown on glucose/(NH4)2SO4 medium resulted in an increase in 2-oxoglutarate decarboxylase activity, which was abolished by the simultaneous addition of cycloheximide. Immunochemical titration, immunoblot analysis and labelling in vivo with antibody raised against 2-oxoglutarate decarboxylase showed that the increase in 2-oxoglutarate decarboxylase activity was due to synthesis of new protein and not to activation of pre-existing protein. The experimental results reported here demonstrate that L-glutamate is assimilated by the pathway, via 2-oxoglutarate, that consists of L-glutamate-oxaloacetate aminotransferase, 2-oxoglutarate decarboxylase and succinate semialdehyde dehydrogenase, rather than by the gamma-aminobutyrate shunt, consisting of L-glutamate decarboxylase and gamma-aminobutyrate aminotransferase.

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Section: Discussionmentioning

confidence: 99%

Effect of l-glutamate on 2-oxoglutarate decarboxylase in Euglena gracilis

Shigeoka

Hanaoka

Kishi

et al. 1992

Biochemical Journal

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“…Acetyl-CoA carboxylase was assayed according to Ernst-Fonberg and Wolpert [27] and acyl-CoA dehydrogenase according to Thorpe [28]. Activities of isocitrate dehydrogenase (NAD'), a marker enzyme of mitochondria [29], glutamate dehydrogenase (NADP'), that of cytosol [30], and glucose-6-phosphatase, that of microsomes [31], were assayed by the methods of references cited.…”

Section: Enzjme Assaysmentioning

confidence: 99%

Fatty acid synthesis in mitochondria of Euglena gracilis

Inui

Miyatake

Nakano

et al. 1984

European Journal of Biochemistry

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A malonyl-CoA-independent fatty acid synthetic system, different from the systems in other subcellular fractions, occurred in mitochondria of Euglena gracilis. The system had ability to synthesize fatty acids directly from acetylCoA as both primer and C , donor using NADH as an electron donor. Fatty acids were synthesized by reversal of fi-oxidation with the exception that enoyl-CoA reductase functioned instead of acyl-CoA dehydrogenase in degradation system. A fairly high activity of enoyl-CoA reductase was found on various enoyl-CoA substrates (C, -C,,) with NADH or NADPH. Three species of enoyl-CoA reductase, distinct from each other by their chain-length specificity, were found in Euglena mitochondria, and one of them was highly specific for crotonyl-CoA. It is also discussed that the mitochondrial fatty-acid synthetic system contributes to wax ester fermentation, the anaerobic energy-generating system found in the organism.We have reported in the preceding paper [I] that when aerobically grown Euglena gracilis is placcd under anaerobic conditions, paramylon, the reserve poly5accharide, is promptly converted into wax esters with concomitant generation of ATP, and this phenomenon has been named as the wax ester fermentation. In Euglena occurrence of four systems of fatty acid synthesis has been reported [2], namely, one involving multifunctional fatty acid synthetase in cytosol [3 -71, two acyl-carrier-protein-dependent systems in chloroplasts (one being a chain-elongation system) [4-6 , 8 -101 and one involving a fatty acid synthetase in microsomes [II, 121. In the wax ester fermentation, thesc known systems of fatty acid synthesis cannot explain the net gain of ATP, since consumption of ATP by formation of malonyl-CoA and transfer of acetyl unit from mitochondria to other subcellular sites exceeds generation of ATP in glycolysis. Existence of an unknown system of fatty acid synthesis which explain the net gain of ATP in wax ester fermentation is accordingly suggested.In the present paper we report that a malonyl-CoA independent fatty acid-synthetic system occurs in mitochondria of E. gracilis and that the system has ability to synthesize fatty acids directly from acetyl-CoA as both primer and C, donor unlike other malonyl-CoA independent systems of fatty acid synthesis in mammalian mitochondria [I 3 -161, chloroplasts of spinach [17] and Mycohacterium smegmutis [18, 191. It is also discussed that the mitochondrial system of fatty acid synthesis contributes to the wax ester fermentation.

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“…The amount of Cbl bound to protein was calculated by subtracting the radioactivity in the solution outside the bag from that in the bag. Assay of some marker and Cbl-dependent enzymes Isocitrate dehydrogenase, a mitochondrial marker enzyme, and glutamate dehydrogenase, a cytosol marker enzyme in Euglena, were assayed by the methods of Oda et al [13] and Tokunaga et al [12] respectively. Glucose-6-phosphatase, a microsomal marker enzyme, was assayed by the method of de Duve et al [14].…”

Section: Cbl-binding Assaymentioning

confidence: 99%

Purification and some properties of cytosolic cobalamin-binding protein in Euglena gracilis

Watanabe

Nakano

Kitaoka

1987

Biochemical Journal

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In Euglena gracilis SM-ZK, a bleached mutant of E. gracilis z, the cobalamin- (Cbl-)binding activity was distributed in cytosol (49.2%), mitochondria (20.3%) and microsomal fraction (20.4%). The cytosolic Cbl-binding activity gave two major peaks in isoelectric focusing. The Cbl-binding protein with pI 3.2 was purified 6500-fold in a yield of 19.9%, and that with pI 4.7 5800-fold in a yield of 11.9%. The monomeric Mr values of both Cbl-binding proteins were about 66,000. The Cbl-binding activity of both proteins showed a very low pH-dependency, and thiol groups and metal ions were not concerned with the Cbl-binding activities. The Ks values of the Cbl-binding proteins with pI 3.8 and 4.7 for CN-Cbl were 1.0 and 2.0 nM respectively. The Cbl-binding protein with pI 3.8 was shown to be immunologically identical with the protein with pI 4.7 by double-immunodiffusion experiments against antibody to the protein with pI 3.8. The two cytosolic Cbl-binding proteins did not show the activities of Cbl-dependent enzymes in E. gracilis, N5-methyltetrahydrofolate:homocysteine methyltransferase, methylmalonyl-CoA mutase and ribonucleotide reductase, suggesting that the two cytosolic Cbl-binding proteins play a physiological role as intracellular Cbl carriers.

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Subcellular Location and Some Properties of Isocitrate Dehydrogenase Isozymes inEuglena gracilis

Cited by 4 publications

References 6 publications

Effect of l-glutamate on 2-oxoglutarate decarboxylase in Euglena gracilis

Effect of l-glutamate on 2-oxoglutarate decarboxylase in Euglena gracilis

Fatty acid synthesis in mitochondria of Euglena gracilis

Purification and some properties of cytosolic cobalamin-binding protein in Euglena gracilis

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