Iron–Sulfur Flavoprotein Dehydrogenases

Singer, Thomas P.; Gutman, Menachem; Massey, Vincent

doi:10.1016/b978-0-12-456001-7.50013-6

Cited by 4 publications

(6 citation statements)

References 159 publications

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“…Maintenance of SDH activity has previously been demonstrated to be temperature dependent (4,25). Similar findings were obtained for the purified enzyme from plant tissues.…”

Section: Methodssupporting

confidence: 74%

“…The preparation was enriched in two polypeptides with apparent mol wt of 67,000 and 30,000 D. These polypeptides migrated with mol wt similar to those reported for the two subunits from both mammalian and yeast SDH (1,4,10,25). The ubiquinone reductase activity to complex 11 (29).…”

Section: Methodsmentioning

confidence: 79%

“…SDH,3 the only enzyme of the Kreb's cycle that is bound to the inner mitochondrial membrane, exists as part of a multiprotein complex (complex II) of the electron transport chain and functions in the transfer of electrons from succinate to ubiquinone-10 (10, 25). The purified mammalian enzyme consists of two dissimilar subunits, a polypeptide with a mol wt of 70,000 and a smaller subunit of 27,000 D (4).…”

mentioning

confidence: 99%

“…Maintenance of an active preparation of SDH in a homogeneous form requires low temperatures, anaero-'Supported in part by a grant from the National Institute of General Medical Sciences (USPHS GM26095) to J. N. S. Cooperative investigation of the United States Department of Agriculture, Agricultural Research biosis, and the presence of protective agents (4,10,25). Partially purified SDH preparations from higher plants have been reported in only a few cases and in none are extensive characterizations of the properties of the resulting products presented (11,12,19).…”

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confidence: 99%

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Succinate Dehydrogenase

Burke

Siedow²,

Moreland³

1982

Plant Physiol.

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A procedure was developed for the partial purification of succinate dehydrogenase from mung bean ( Vigna radiata L.) hypocotyls and soybean (Glycine max ILl Meff. v. Ransom) cotyledons. The procedure utilized a Triton X-100 extraction foDlowed by ammonium sulfate precipitation. The final fraction was enriched in two polypeptides with approximate molecular weights of 67,000 and 30,000 daltons, exhibited a pH optima of 7.0 to 7.5, contained a b-type cytochrome, and exhibited the characteristic ferredoxintype and high potential iron-sulfur protein-type electron paramagnetic resonance signals reported for the iron-sulfur centers of mammalian succinate dehydrogenase. Inhibition constants of 1.15 and 24.6 micromolar for oxaloacetate and malonate, respectively, were obtained.

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“…Maintenance of SDH activity has previously been demonstrated to be temperature dependent (4,25). Similar findings were obtained for the purified enzyme from plant tissues.…”

Section: Methodssupporting

confidence: 74%

Section: Methodsmentioning

confidence: 79%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Succinate Dehydrogenase

Burke

Siedow²,

Moreland³

1982

Plant Physiol.

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“…At 450 nm both iron-sulfide and flavin absorb, whereas at 550 nm the absorbance is due only to the iron-sulfide linkages (19). Titration with dithionite indicated that about 60% of the absorbance at 450 nm is due to flavin.…”

Section: Resultsmentioning

confidence: 99%

Glutamine-Binding Subunit of Glutamate Synthase and Partial Reactions Catalyzed by This Glutamine Amidotransferase

Trotta¹,

Platzer²,

Haschemeyer³

et al. 1974

Proc. Natl. Acad. Sci. U.S.A.

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In the course of studies on glutaminedependent carbamyl phosphate synthetase from Aerobacter aerogenes, we purified another protein which was found to be glutamate synthase (EC 2.6.1.53). The enzyme, obtained in apparently homogeneous form (monomer molecular weight about 227,000; s2ow = 17.6 S), was found to be a typical glutamine amidotransferase in that it exhibits glutaminase activity and can utilize ammonia in place of glutamine as a nitrogen donor. Earlier work in this laboratory showed that glutamine-dependent carbamyl phosphate synthetase from Escherichia coli consists of a heavy subunit which can catalyze the synthesis of carbamyl phosphate from ATP, bicarbonate, and ammonia (but not from glutamine), and a light subunit which functions to bind glutamine (1, 2). In subsequent hybridization experiments with glutamine dependent carbamyl phosphate synthetase from Aerobacter aerogenes, it was found that the light subunit of the A. aerogenes enzyme could combine with the heavy subunit of the E. coli enzyme to form an active glutamine-dependent hybrid enzyme; similarly, an active hybrid enzyme could be prepared from the light subunit of the E. coli enzyme and the heavy subunit of the A. aerogenes enzyme.* In the course of isolating glutamine-dependent carbamyl phosphate synthetase from A. aerogenes, we noted during a gel filtration step in the procedure that another protein had also been purified (see first peak, Fig. 1). The catalytic properties of this protein were initially obscure, but we decided to pursue study of this apparently homogeneous protein after we found that it exhibited glutaminase activity and that it could be split to a heavy and a light subunit when subjected to polyacrylamide gel electrophoresis in sodium dodecyl sulfate.These observations led us to think that the new protein might be a glutanmine amidotransferase, and after testing it for the activities of the several known enzymes in this category we discovered that the new protein is glutamate synthase (EC 2.6.1.53) whose major catalytic activity is to form glutamate from a-ketoglutarate and glutamine according to the following reaction (3-5): a-ketoglutarate + TPNH + H+ + L-glutamine 2 L-glutamate + TPN+ Several glutamine amidotransferases [e.g., carbamyl phosphate synthetase (1, 2), anthranilate synthetase (6), p-aminobenzoate synthetase (7) ] are composed of a heavy and a light subunit, and there is strong evidence in each case that the light subunit has the function of binding glutarmine; the amide nitrogen is then transferred to the heavy subunit for use in the corresponding synthesis reactions. We therefore expected that the light subunit of A. aerogenes glutamate synthase would contain the glutamine binding site of this enzyme. However, as described here, we found that the glutamine binding site of glutamate synthase is located on the heavy subunit. Miller and Stadtman (8,9) had previously shown that glutamate synthase from E. coli is an iron-sulfide flavoprotein. We have found that the A. aerogenes glutamate synthase is a...

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