The metabolism of oxalate precursors in isolated perfused rat livers

Liao, Lon Lon; Richardson, K.E.

doi:10.1016/0003-9861(72)90361-x

Cited by 50 publications

(20 citation statements)

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“…It is assumed that the substrate is the hydrated form of glyoxylate CH(0H2)COOH, and, as such, it is an a-hydroxyacid analog. The implication that glycolate oxidase is responsible for the in vivo synthesis of oxalate from glyoxylate is paralleled by similar considerations in the case of rat liver (15). On the other hand, mammalian lactate dehydrogenase (EC 1.1.1.27), which can catalyze the dismutation of glyoxylate to glycolate and oxalate (23), has been considered the main enzyme catalyzing the oxidation of glyoxylate to oxalate in leucocytes and erythrocytes (25) as well as in the cytosol of human liver and heart (11).…”

mentioning

confidence: 73%

Synthesis of Oxalic Acid by Enzymes from Lettuce Leaves

Davies¹,

Asker²

1983

Plant Physiol.

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A rapid purification of lactate dehydrogenase and glycolate oxidase from lettuce (Lactuca saliva) leaves is described. The kinetics of both enzymes are reported in relation to their possible roles in the production of oxalate. CH(0H2)COOH, and, as such, it is an a-hydroxyacid analog. The implication that glycolate oxidase is responsible for the in vivo synthesis of oxalate from glyoxylate is paralleled by similar considerations in the case of rat liver (15). On the other hand, mammalian lactate dehydrogenase (EC 1.1.1.27), which can catalyze the dismutation of glyoxylate to glycolate and oxalate (23), has been considered the main enzyme catalyzing the oxidation of glyoxylate to oxalate in leucocytes and erythrocytes (25) as well as in the cytosol of human liver and heart (11).The demonstration by Betsche et al. (2) that some green leaves contain lactate dehydrogenase raises the possibility that it plays a part in the production of oxalate in leaves. In this paper, we examine this possibility and suggest that the oxidation of glyoxylate to oxalate involves the interaction of lactate dehydrogenase and glycolate oxidase. lettuce leaves (400 g) were homogenized with 40 g of insoluble Polyclar and 400 ml of K-phosphate (pH 7.4, 0.1 M) containing fl-mercaptoethanol (5 mM). Prior to homogenization, the mixture was deoxygenated by bubbling N2. After homogenization, the extract was squeezed through cheese cloth and centrifuged at 23,000g for 25 min. The supernatant was fractionated with (NH4)2SO4, the fraction precipitating between 25 and 55% saturation was collected by centrifuging (23,000g for 20 min), dissolved in 50 ml of Tris-HCl buffer (pH 8.0, 5 mM), and dialyzed against 5 L of the same buffer. The buffer was changed until no (NH4)2SO4 could be detected by Nesslers reagent. Any precipitate was removed by centrifuging at 32,000g for 10 min and the clear solution poured on to a DEAE-cellulose column (2.5 x 30 1m) previously equilibrated with the same buffer. When the extract had passed through the column, the column was washed with 50 ml of the buffer used for equilibration. The enzymes were eluted with a linear gradient of KCl (0-0.5 M) in 500 ml of the same buffer, and 5-ml fractions were collected. Glycolate oxidase emerged as a single peak followed by a single peak of lactate dehydrogenase. MATERIALS AND METHODSPurification of Glycolate Oxidase. The peak fractions were combined and dialyzed for 4 h against K-phosphate (pH 6.3, 50 mM) and any precipitate which formed was removed by centrifuging at 32,000g for 10 min. The clear solution was applied to a column (1.5 x 12 cm) of Sepharose-aminohexyl oxamate previously equilibrated with K-phosphate (pH 6.0, 50 mM). When the extract had passed through the column, the column was washed with a solution of KC1 (0.5 M) in the same buffer until pigments present in the extract had reached the bottom of the column. The pigments (and a small amount of glycolate oxidase) were removed by washing the column with 3 bed volumes of buffer without KCl. The enzyme was then el...

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confidence: 73%

Synthesis of Oxalic Acid by Enzymes from Lettuce Leaves

Davies¹,

Asker²

1983

Plant Physiol.

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“…Aliments rich in oxalate are cacao, spinach, or rhubarb [8]. Endogenous oxalate production mainly occurs in hepatocytes [9,10] where oxalate's main precursor glyoxylate [11][12][13] can be converted to oxalate by peroxisomal glycolate oxidase (GO) and by cytoplasmatic lactate dehydrogenase (LDH, Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

Glyoxylate is a substrate of the sulfate-oxalate exchanger, sat-1, and increases its expression in HepG2 cells

Schnedler

Burckhardt

2011

Journal of Hepatology

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“…Ascorbate is metab olized to oxalate, and it has been found that about 40 % of urinary oxalate originates from dietary as corbate {Atkins et al, 1964;Liao and Richardson, 1972 In this study 1,000 mg (578 jumol) of ascorbate were given daily for 3 weeks. This resulted in in creased oxalate excretion in all subjects investi gated.…”

Section: The Effect Of Pyridoxine On the Urinary Excretion Of Oxalatementioning

confidence: 99%