Studies on Biological Oxidations

Barrón, E. S. Guzmán; Demeio, R. H.; Klemperer, Friedrich W.

doi:10.1016/s0021-9258(18)74946-6

Cited by 152 publications

(9 citation statements)

References 23 publications

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“…Moreover, inhibition or promotion of DNA cleavage is not observed appreciably under aerobic and anaerobic conditions suggesting that oxidative cleavage is not a factor. 47 Hence, the DNA cleavage observed here is expected to occur through a hydrolytic process (Fig. 7).…”

Section: Cleavage Of Pbr322 Plasmid Dna By Copper(ii) Complexesmentioning

confidence: 84%

Potentially cytotoxic new copper(ii) hydrazone complexes: synthesis, crystal structure and biological properties

2013

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A new set of penta-coordinated copper(II) hydrazone complexes containing solvated methanol were synthesized by reacting the hydrazone ligands, 2-acetylpyridine benzoyl hydrazone (HL1) and 2-acetylpyridine thiophene-2-carboxylic acid hydrazone (HL2), with [CuCl2(DMSO)2] and characterized by different spectral methods. Single crystal X-ray diffraction studies of the complexes revealed that both of them, [CuCl(L1)(MeOH)] (1) and [CuCl(L2)(MeOH)] (2), have square pyramidal geometry around the cupric ion, in which the hydrazone is coordinated through NNO atoms along with a molecule of methanol in the apical position. Interaction of the ligands HL1 and HL2 along with the corresponding copper complexes 1 and 2 with calf thymus DNA (CT-DNA) has been estimated by absorption and emission titration methods which revealed that the compounds interacted with CT-DNA through intercalation. Binding of the compounds, i.e., free ligands and complexes (1) and (2) with bovine serum albumin (BSA) protein investigated using UV-visible, fluorescence and synchronous fluorescence spectroscopic methods indicated that there occurred strong binding of copper complexes to BSA over the ligands. Further, the cytotoxicity of the compounds examined in vitro on a panel of cancerous cell lines such as a human cervical cancer cell line (HeLa), a pancreatic cancer cell line (PANC-1), an Ehrlich ascites cancer cell line (EAC) and Dalton's lymphoma ascitic cancer cells (DLA) and a normal mouse embryonic fibroblasts cell line (NIH3) demonstrated that the complexes 1 and 2 possessed superior cytotoxicity than that of well-known commercial anticancer drug cisplatin to the tumor cells but are less toxic to the normal cell line and have emerged as potential candidates for further studies.

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Section: Cleavage Of Pbr322 Plasmid Dna By Copper(ii) Complexesmentioning

confidence: 84%

Potentially cytotoxic new copper(ii) hydrazone complexes: synthesis, crystal structure and biological properties

2013

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“…This could be due to differences in surface conditions when powders are used in place of solid plate of iron. However, the slight copper impurity found in the iron powder used in this study could be the cause of this discrepancy even though the maximum copper concentration possible in these solutions was only 3 parts per billion (ppb), a full order of magnitude less than the 0.05-ppm copper contamination level deemed safe and appropriate for noncatalyzed ascorbic acid studies (Barron et al, 1936;Timerlake, 1960). Joslyn and Miller (1949) reported very similar ty2 values when 0.07-ppm levels of both cupric and ferric ion were present in ascorbic acid solutions of pH similar to the present study.…”

Section: Discussionmentioning

confidence: 80%

Corrosion of iron by ascorbic acid and catalysis of ascorbate oxidation by products of the iron corrosion

Rosanoff¹,

Briggs²,

Lumen³

1985

J. Agric. Food Chem.

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Electrolytic iron (99.8% Fe) prepared as small plates was exposed to oxygenated solutions of ascorbic acid. Gravimetric corrosion rates and ascorbate oxidation rates were measured simultaneously in a new apparatus designed for that purpose. The mean corrosion rate was high for iron in 1 mM ascorbic acid at 365 mdd (mg dm-2 day-1) (6-h tests, n = 12) and was highly dependent upon ascorbate concentration, increasing to 3200 mdd in 11 mM ascorbic acid. Corrosion of iron in oxygenated, deionized water was zero for these tests. Ascorbic acid oxidation under these oxygenated conditions agreed well with the first-order rate model. Ascorbate oxidation proceeded slowly in the absence of iron. Mean kx (first-order rate constant) was increased 4-5 times by the presence of an elemental iron plate in the solution and 10 times by the addition of fine electrolytic iron powder (99.9% Fe). In these nonbuffered solutions, the ascorbate oxidation rate was unchanged when iron corrosion from plates was doubled or tripled in the solutions. High concentrations of iron powder in the solutions did not cause higher rates of ascorbate oxidation than small amounts of iron. Nutritional and food processing implications of these results are discussed.

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“…Ascorbic acid is oxidized readily by molecular oxygen at neutral pH in the presence of cupric ions as a catalyst. The reaction was considered by Barton et al (12) to proceed as follows. ~--- As can be seen in Table II, a combination of cupric ions and potassium ascorbate produced an inhibition of the incorporation of sulfate by the cartilage slices which was considerably greater than was the sum of the inhibitions produced by each alone.…”

Section: Effect Of Ascorbie Acid Oxidationmentioning

confidence: 99%

The Effect of Ascorbic Acid Oxidation on the Incorporation of Sulfate by Slices of Calf Costal Cartilage

Klebanoff

Dziewiatkowski

Okinaka

1958

The Journal of General Physiology

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A marked inhibition of the incorporation of S35-sulfate by normal calf costal cartilage was produced by potassium ascorbate in the presence of catalytic amounts of cupric ions. The effect of the various components of the ascorbic acid oxidizing system (potassium ascorbate, cupric ions, cuprous ions, hydrogen peroxide, dehydroascorbie acid) was investigated. The results of experiments in which hydrogen peroxide, catalase, or sodium azide were used singly or in combination suggest that the inhibition produced by the aseorbic acid oxidizing system is due, to a considerable extent, to the production of hydrogen peroxide. Dehydroaseorbie acid was also found to inhibit the incorporation of S35-sul/ate by cartilage slices. However, the gradual fall in pH which resulted from the addition of dehydroaseorbic acid could account to a large extent for the inhibitory effect observed because the incorporation of S35-sulfate by cartilage slices decreases sharply as the pH is lowered. The incorporation of SSS-sulfate by cartilage slices is inhibited also by increasing the concentration of phosphate.The state of ascorbic acid deficiency is associated with a defect in the production of intracellular ground substance. The component of ground substance primarily affected, and the mechanisms involved, have not, as yet, been clearly elucidated. A decrease in the incorporation, of S35-sulfate into granulation tissue (1-3), cartilage (4), and a number of other tissues (5) has been observed in scorbutic guinea pigs. Earlier work (6, 7) has established that most of the S36-sulfate retained by an animal beyond 24 hours is found in sulfated mucopolysaccharides. Bostr6m and M~.nsson (8) have studied the incorporation of S36-sulfate into the chondroitin sulfate of costal cartilage slices prepared from normal calves and have indicated a number of factors which influence this reaction. The influence of ascorbic acid on the incorporation of SSS-sulfate by slices of costal cartilage from normal calves is considered in the present communication.* Arthritis and Rheumatism Foundation Fellow.

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Studies on Biological Oxidations

Cited by 152 publications

References 23 publications

Potentially cytotoxic new copper(ii) hydrazone complexes: synthesis, crystal structure and biological properties

Potentially cytotoxic new copper(ii) hydrazone complexes: synthesis, crystal structure and biological properties

Corrosion of iron by ascorbic acid and catalysis of ascorbate oxidation by products of the iron corrosion

The Effect of Ascorbic Acid Oxidation on the Incorporation of Sulfate by Slices of Calf Costal Cartilage

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