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Biomedical subjects

A Gemant

Publications and source records attributed to A Gemant.

10 recordsLinked to original sources
PubMed1981

Alteration of DNA by hydrogen peroxide.

DNA is altered by the action of hydrogen peroxide, a ubiquitous body constituent. Formation of damaged species is established by changes in four characteristics of DNA: absorption in the ultraviolet, complexing with histone, adsorption by anion exchange resin and charcoal, binding of silver cations. Damaged species of DNA might lead to impaired function of the organism. Gamma globulin by complexing with DNA is a partial inhibitor of this attack by hydrogen peroxide.

Adsorption↗
PubMed1979

Histone: oxidation by peroxidase alters its interaction with DNA.

When histone is oxidized by peroxidase, its basicity (hence its complexing with DNA) is reduced: this reduction causes further alterations in the effect of histone upon the heat denaturation, acid precipitation, and breakdown by DNase of DNA, alterations which indicate that the regulation by histone of DNA expression may become abnormal. If oxidized species of histone should accumulate in the tissues in old age, the alteration mentioned might be a contributory factor of senescence.

Animals↗
PubMed1979

Inhibitors of oxidative degradation of protein: gerontological implications.

Compounds were studied that inhibit the oxidative degradation of human serum albumin by peroxidase and the enzyme model, iron hydroxide. Differences between the two oxidants gave clues for the mechanism of inhibition. The inhibitors studied were inorganic anions, phosphate, sulfate, carbonate and molybdate; organic anions, decanoate and glycocholate; and the nonionic species, glycogen. Such inhibitors might be considered as adjuvants in senescence: by decreasing the rate of enzymic oxidation of essential body proteins, they would, in the course of aging, reduce some of the physiological changes occurring as a result of accumulation of degraded protein.

Aging↗
PubMed1978

Iron hydroxide: model for enzymes that oxidize proteins.

The particles of an iron hydroxide sol were found to be a suitable model for protein-oxidizing enzymes such as peroxidase and polyphenol oxidase. In addition to small molecules such as pyrogallol, human serum proteins, albumin and gamma-globulin, are shown to be substrates of the oxidizing model. The activity is markedly increased by the addition of small amounts of copper to the iron in the particles of the sol. The size and molecular weight of the enzyme model, as well as the number of active centers were determined.

Blood Proteins↗
PubMed1977

Inhibition of oxidation by peroxidase of human serum proteins.

The oxidation of essential serum proteins, albumin and gamma globulin, by the enzyme peroxidase can be partially inhibited by compounds, such as EDTA and 2,4-pentanedione, that complex with the iron ion in peroxidase. The importance of such inhibition lies in the circumstance that the oxidations in question might be a possible causative factor in tissue aging.

Acetone↗
PubMed1977

Polyphenol oxidase as a factor in aging.

Polyphenol oxidase oxidizes several proteins that contain tyrosine. During aging, when synthesis and replacement of catabolized proteins are lagging, the relative proportion of oxidized species might reach high values, thus impairing physiological function. A mathematical analysis verifies this assumption.

Aging↗