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E I Tiktopulo

Publications and source records attributed to E I Tiktopulo.

6 recordsLinked to original sources
PubMedDate not supplied

[Temperature changes in ribonuclease].

Deuteroexchange kinetics of ribonuclease is studied by the change of IR-spectra in the range of 1400--1900 cm-1 at different temperatures in solutions with two pD values, 2.6 and 5.1. It is shown that in the pre-denaturational temperature range the enthalpy of unfolding is 1.5 kcal/mol, i. e. two orders lower than the enthalpy of unfolding in the denaturational temperature range (100--120 kcal/mol). Thus in the pre-denaturational range of temperatures the disclosure of a compact protein structure can proceed at the expense of separate non-cooperative disruptures of bonds. However, the concentration of these disruptures is so low that they cannot give an explanation to the observed pre-denaturational macroscopic changes of protein.

Animals↗
PubMedDate not supplied

[Study of conformational transformations in serum albumin by the method of scanning microcalorimetry].

Thermal denaturation of serum albumin in the alkali pH region is investigated by the scanning microcalorimetry method. It is shown that at pH 8.5 a macromolecule undergoes a conformational transformation as a result of which its thermal characteristics are changed qualitatively. The form which corresponds to lower pH values is denatured according to the smaller than all or none greater than model with an intensive sorption of heat. The form corresponding to higher pH values is denatured noncooperatively without heat absorption but with an essential increase of heat capacity.

Calorimetry↗
PubMedDate not supplied

[Number of hydrogen bonds in the structure of collagen].

The kinetics of hydrogen exchange of collagens from different animals was studied by the radioisotopic method (tritium) and infrared spectroscopy (deuterium). It has been shown that collagens from different animals (rat, pike, cod, carp, frogs) differ in amino acid composition and thermostability but are similar in the amount of slowly exchanged hydrogens. All the studied collagens have (1.00 +/- 0.05) very slowly exchanged hydrogens per triplet and (0.6 +/- 0.1) slowly exchanged hydrogens per triplet. Identifying the quantity of slowly exchanged hydrogens with the quantity of hydrogen bonds in the macromolecule, it can be concluded that collagens differing in stability do not differ by the quantity and composition of intramolecular hydrogen bonds.

Animals↗
PubMedDate not supplied

[Mobility of collagen structure and temperature adaptation of animals].

The method of hydrogen exchange is used to determine the mobility of acid-soluble collagen molecules from animals with different physiological temperature in terms of equilibrium constants of the formation of micro-unfolding or fluctuating defects of the structure. It has been shown that mobility of the collagen structure correlates with the physiological temperature of the animal from whose tissue collagen was isolated and is mainly determined by the amino acid content of the collagen. It has been shown also that at physiological temperatures characteristic for a particular species the level of collagen mobility is of the same order despite their different thermostability. The conclusion has been drawn that the level of mobility is the main criterion at the natural selection of the amino acid composition of collagens in different animals.

Adaptation, Physiological↗