Received for publication 8 December 1965. reduced copper is oxidized to cupric ions by means of iodine. If no necessary allowance has been made, the cupric ions formed would be completely reduced and precipitated as cuprous iodide in the presence of an excess of soluble iodide in the reagent. Probably to check this reduction by iodide, Harding and Downs (1933) employed potassium oxalate in thei...

The tumor-inhibitory jxitency of combinations of the cupric chelate of kethoxal bis(thiosemicarbazone) [Cu(II)KTS] with several compounds that cause inhibition of the synthesis of DNA by different biochemical mechanisms was assessed in Sarcoma 180 ascites cells. Cu(II)KTS prolonged the survival time of tumor-bearing mice, whereas neither cupric chloride, copper stéarate,nor kethoxal bis(thiose...

We studied the effect of different concentrations of alpha-tocopherol on in vitro cupric ions induced oxidation of low density lipoproteins (LDL). Human native LDL (50 µg protein/ml) oxidation was induced by 10 µmol/L of CuSO4. Conjugated dienes were measured spectrophotometrically for up to 440 minutes. The length of the lag phase (Tlag), maximum velocity of the reaction (Vmax) and the maximum...

The presence of cupric ions or ferric ions was found to enhance the development of color in the indole reaction for the calorimetric determination of deoxyribonucleic acid. The addition of calcium, cobaltous, magnesium, manganous, nickel, or zinc ions did not produce this effect. In the absence of added cupric ions, the indole reaction gave variable results, and the color developed to less than...

The tumor-inhibitory jxitency of combinations of the cupric chelate of kethoxal bis(thiosemicarbazone) [Cu(II)KTS] with several compounds that cause inhibition of the synthesis of DNA by different biochemical mechanisms was assessed in Sarcoma 180 ascites cells. Cu(II)KTS prolonged the survival time of tumor-bearing mice, whereas neither cupric chloride, copper stéarate,nor kethoxal bis(thiose...

In the course of a comparative study of several methods for the determination of sugar in blood, the results of which will be recorded elsewhere, it became desirable to investigate the reaction betsveen copper sulfate and potassium iodide which is concerned in a number of methods for sugar determination (Bang (l), Maclean (2), Scales (3), Lehmann (4), Riegler (4), Peters (4), Kendall (5)). In c...

In a study of the mechanism of activation of the copper enzyme, ascorbic acid oxidase, it was observed that most compounds which activate this enzyme have the common property of forming complex compounds with cupric ion (l-3). Among these activating substances were ribonucleic acid,’ deoxyribonucleic acid, and certain of their constituents. These substances showed a surprisingly strong affinity...

Cupric phenanthroline was used to catalyze the formation of disulfide bonds in cAMP-dependent protein kinase II. Incubation of holoenzyme alone with cupric phenanthroline resulted in no disulfide bond formation. In contrast, when holoenzyme was preincubated with cAMP prior to treatment with cupric phenanthroline, specific interchain disulfide bonding was found between the regulatory (R) and cat...