Sodium Oxamate Research Articles

Improved serum initiated aspartate aminotransferase assay by inhibition of lactate dehydrogenase with oxamate

We describe a serum-inititated aspartate aminotransferase (EC 2.6.1.1) assay that obviates the need for added lactate dehydrogenase (EC 1.1.1.27) in the reagent system. Interference from the oxidation of NADH by endogeneous lactate dehydrogenase is eliminated by adding sodium oxamate, a competitive inhibitor of the enzyme. The advantages of oxamate inhibition over lactate dehydrogenase addition are a shorter preincubation period, an increase in the linear range from less than 600 to more than 1400 U/L, no interference from above-normal concentrations of ketoacids, and elimination of bias between serum-initiated and the standard oxoglutarate-initiated assays for aspartate aminotransferase.

Vibrational spectra and structure of crystalline oxamic acid and sodium oxamate

Abstract Laser Raman and i.r. spectra of crystalline oxamic acid and its sodium salt have been investigated in the region 4000-40 cm −1 . Cyclic centrosymmetric dimeric structures involving the OH group in the acid and the NH 2 group in the sodium salt are proposed to explain the spectral features of these materials. Tentative vibrational assignments for the observed spectra are proposed based on a modified oriented gas model.

Infrared and far-infrared spectra of solid oxamic acid, deutero-oxamic acid and their salts

The i.r. and far-i.r. room temperature spectra of oxamic acid, deutero-oxamic acid, sodium oxamate, sodium deutero-oxamate, potassium-, barium-, and copper(II) oxamates, and potassium bis(oxamato)cuprate(II) are reported. The group vibrations of oxamic acid, sodium oxamate, and potassium bis(oxamato)cuprate(II) are assigned and discussed. A normal coordinate analysis of oxamic acid and oxamide is presented and a discussion of the similarities is given. The spectral evidence indicates that oxamic acid does not exist as the zwitterion in the solid state.

Metabolic pathway of L-3-methoxy-4-hydroxyphenylalanine (3-O-methyl dopa) - participation of tyrosine aminotransferase, aromatic .ALPHA.-keto acid reductase and lactate dehydrogenase.

The metabolic pathway of L-3-methoxy-4-hydroxyphenylalanine (3-O-methylDOPA) in the rat was investigated in vivo and in vitro. When 3-O-methylDOPA-14C was incubated with rat liver homogenate, 3-methoxy-4-hydroxyphenylpyruvic acid (MHPP) was detected as the major metabolite, on addition of sodium α-ketoglutarate. Without α-ketoglutarate. 3-O-methylDOPA remained unchanged, indicating that the transamination between 3-O-methylDOPA and α-ketoglutarate is the first step in the metabolism of 3-O-methylDOPA. The enzyme responsible for the transamination was identified as tyrosine aminotransferase. After oral administration of MHPP-2-14C to rats, 3-methoxy-4-hydroxyphenyllactic acid (MHPL) and homovanillic acid (HVA) (the major urinary metabolites of 3-O-methylDOPA) were detected as the major metabolites. Using rat liver homogenate, it was revealed that MHPP-2-14C is transformed to MHPL with NADH but not with NADPH. Lactate dehydrogenase (LDH) was obtained from rat liver and MHPP was shown to be a substrate of LDH. It was recognized, however, that there is another dominant enzyme reducing MHPP to MHPL. This enzyme was purified from rat liver and identified as aromatic α-keto acid reductase (AKAR). Inhibition of sodium oxamate was over 95% against LDH and below 10% against AKAR, respectively, using MHPP as a substrate. Utilizing this differential inhibition of oxamate, the relative contribution of the two enzymes to the formation of MHPL from MHPP was estimated in rat tissues as 1.2-15.7% for LDH and 84.3-98.8% for AKAR, respectively.

Selective in vitro cytotoxicity of a glycolytic enzyme inhibitor for immature lymphoid cells.

Summary. A specific lactate dehydrogenase inhibitor, sodium oxamate, which prevents glycolytic resynthesis of ATP, has been shown to possess a significant, in vitro cytotoxic effect for EB2 cells and for the acute leukaemia lymphoblast. This result was obtained at an oxamate concentration of 0.08 M in TC 199 medium adjusted to physiological osmolality, in comparison with control cultures containing an equimolar concentration of sodium chloride. No significant oxamate cytotoxicity was found for normal marrow myeloid precursors or for blood lymphocytes and neutrophils, although a significant reduction in glycolysis‐dependent neutrophil phagocytosis was obtained.

Inhibition of thyroid secretion by sodium fluoride in vitro

NaF mimicked the activation by thyrotropin of iodide binding to proteins and of glucose C- I oxidation but not the accumulation of intracellular colloid droplets or the stimulation of secretion in dog thyroid slices in vitro. On the contrary, NaF inhibited the two latter thyrotropin effects. The inhibitory action of F − was partially relieved by the addition of glucose to the medium; it was mimicked by sodium oxamate. These data suggest that NaF depresses the endocytosis of colloid and thyroid secretion by inhibiting aerobic glycolysis in the follicular cell. NaF inhibited the activation of colloid droplet accumulation and secretion by N 6, O 2′-dibutyryl-adenosine 3′,5′-monophosphate (dibutyryl cyclic AMP) and the accumulation of cyclic AMP in thyrotropin-stimulated slices. This suggests an inhibition at the level of both cyclic AMP accumulation and cyclic AMP action. The inhibition by NaF and sodium oxamate of colloid droplet formation and thyroid secretion but not of glucose C- I oxidation in stimulated slices further confirms our conclusion that the latter effect is not merely a consequence of the activation by thyrotropin of colloid endocytosis.

Antibody to lactate dehydrogenase II. Inhibition of glycolysis and growth of tumor cells

1. 1. The effect of antibody to lactate dehydrogenase ( L-lactate:NAD + oxidoreductase, EC 1.1.1.27) on the glycolysis and growth in vitro of rabbit Vx-2 tumor cells, mouse Ehrlich carcinoma cells, and embryonic rabbit kidney and skeletal muscle cells were studied. 2. 2. During 90-min Warburg respirometer studies, antibody to rabbit lactate dehydrogenase (anti-lactate dehydrogenase) caused no significant inhibition of anaerobic glycolysis by intact rabbit Vx–2 tumor cells but inhibited 19% of their aerobic glycolysis. Antibody to mouse lactate dehydrogenase caused no inhibition of either aerobic or anaerobic glycolysis of Ehrlich cells during this time. Sodium oxamate (3.10 −2 M), a competitive inhibitor of lactase dehydrogenase, inhibited anaerobic glycolysis of Ehrlich cells by 51% and aerobic glycolysis by 71–100%. 3. 3. With Vx–2 tumor cells growing in vitro both anti-lactate dehydrogenase and sodium examate significantly inhibited lactic acid formation and glucose uptake from the earliest time intervals (10 h) tested and almost totally inhibited tumor cells reproduction. 4. 4. With Ehrlich carcinoma cells growing In vitro sodium oxamate inhibited glycolysis by 10 h or sooner and anti-lactate dehydrogenase inhibited glycolysis after a 24-h lag. Both agents inhibited cell reproduction. 5. 5. Rates of lactic acid formation and protein synthesis by non-malignant embryonic rabbit kidney and muscle cells growing in vitro were not affected by antilactate dehydrogenase. Sodium oxamate partially inhibited glycolysis and protein synthesis by these cells.

Effect of oxamate on oxidation of specifically labeled glucose by Ehrlich ascites carcinoma cells.

SummaryThe oxidation of specifically labeled glucose (0.01 M) by whole Ehrlich ascites carcinoma cells in the presence of sodium oxamate (0.01 M, 0.03 M, 0.06 M) was investigated. With increase in concentration of oxamate, the expired C14O2 is strikingly increased with glucose-6-C14 substrate and essentially unchanged with glucose-1-C14 substrate. Simultaneously, the amounts of residual glucose increase and of accumulated lactate decrease.