[Mechanism of polyene antibiotic inactivation. Possible ways for levorin stabilization].

Various means for levorin isolation were studied with the EPR method and approaches to stabilization of the antibiotic on storage under natural conditions were discussed. It was shown that formation of the radicals begins already at the first stage of the antibiotic isolation, i.e.

[Mechanism of polyene antibiotic inactivation. The effect of amino sugar oxidation on polyene chain destruction].

Changes in the acid-base characteristics of levorin during its inactivation are discussed. It is shown that with a decrease in the biological activity a change in the basic characteristics of the levorin amino sugar moiety takes place. The kinetic studies with model compounds, i.

[Mechanism of polyene antibiotic inactivation. Changes in the physicochemical characteristics and the destruction of the polyene chromophore levorin during inactivation].

The results of studying free radicals of some polyenic antibiotics with the EPR method are presented. It is shown that the number of free radicals increased by 100 per cent with a 2-fold decrease in the biological activity. A qualitative change in the EPR spectrum due to the presence of a new radical type was also observed.

[Use of the aliphatic amine reaction with 2,5-dinitrophenol in antibiotic analysis].

Possible use of dinitrophenol reaction with amines in quantitative determination of amines and amino sugars in various antibiotics was investigated. It was found that the reaction with 2,5-dinitrophenol (2,5-DNP) in dimethylsulfoxide (DMSO) providing the highest batochromic shift in the electron spectra was most suitable. Selectivity of the 2,5-DNP reaction with respect to mycosamine contained in polyenic antibiotics was shown.

[Inactivation mechanism of polyene antibiotics. The change in the functional component of levorin during inactivation].

The inactivation process of levorin, a polyenic antibiotic was studied in the presence of oxygen. It was found that the biological activity did not sufficiently correlate with the optical density of the antibiotic solution. This indicates that destruction of the double bonds was not the only process resulting in the biological activity loss.