[Dependence of extracellular proteases synthesis on the growth phase of Pseudomonas fluorescens]. / Zavisimost' sinteza vnekletochnykh proteaz ot fazy rosta u Pseudomonas fluorescens.

The aim of this work was to study the dependence of the synthesis of exocellular proteolytic enzymes on the growth phase of Pseudomonas fluorescens which was cultivated in media containing amino acids as a sole carbon source. In all of the studied cases, the proteolytic activity of the medium increased in parallel to the bacterial growth until the culture reached the stationary growth phase. Chloramphenicol added in the phase of intensive growth ceased the increase of the proteolytic activity of the medium without a noticeable delay in time. This fact indicates that the processes of translation and secretion of exoproteases occur virtually at the same time in the cell of P. fluorescens. The rate of degradation of exocellular proteolytic enzymes was shown to be insignificant in comparison to the rate of their synthesis. Therefore, the increase in the proteolytic activity of the medium directly reflects the rate of synthesis of exoproteases.

[Localization of metabolites which are regulators of extracellular protease synthesis in Pseudomonas fluorescens bacteria]. / O lokalizatsii metabolitov--reguliatorov sinteza vnekletochnykh proteaz u bakterii Pseudomonas fluorescens.

The effect of over forty low molecular weight substrates on the growth and synthesis of exocellular neutral proteases was studied in Pseudomonas fluorescens. Neutral exoproteases were found to be regulated enzymes. Glucose did not repress the synthesis of exocellular proteases; the regulation of their synthesis by amino acids involved the mechanism of induction. The data suggest that the primary intracellular inductors of the synthesis of exoproteases are formed for different groups of amino acids at different levels of their utilization by the cells, viz. at the level of transport and at the level of the first steps in the degradation of their carbon backbones. The paper discusses possible molecular mechanisms for integrating the signal of the primary intracellular inductors, which directly regulate the activity of the operon(s) of neutral exocellular proteases.

[Absorption and magnetic circular dichroism spectra of nonequilibrium states of hemoproteins. II. Myoglobin and its complexes]. / Spektry pogloshcheniia n magnitonogo krugovogo dikhroizma gemsoderzhashchikh blekov v neravnovesnykh sostoianiiakh. II. Mioglobin i ego kompleksy.

Absorption and magnetic circular dichroism spectra of non-equilibrium states of myoglobin and its complexes formed by reduction oxidased forms of proteins by thermalysed electrons at 77 degrees K were studied. Mixtures of high spin and low spin ferroforms were observed for nonequilibrium states of myoglobin and its complex with fluorine, the content of the high spin form is larger in the complex. Two intense peaks were found in the alpha-band region of absorption spectra of myoglobin and its spectra with F-, OH- and imidazole. This effect is due to lowering of the active centre's symmetry. Similarity of spectral characteristics of low spin ferroforms of these complexes was explained by the strong influence of distal histidine. The low temperature reduction of azide and cyanide complexes of myoglobin led to formation of nonequilibrium low spin ferroforms whose spectra demonstrate the presence of N3- and CN- in heme iron's coordination sphere. The temperature relaxation of all nonequilibrium systems were investigated.

[Absorption spectrum and magnetic circular dichroism of heme-containing proteins in nonequilibrium states. I. Hemoglobin and its derivatives]. / Spektry pogloshcheniia i magnitnogo krugovogo dikhroizma gemosoderzhashchikh belkov v neravnovesnykh sostoianiiakh. I. Gemoglobin i ego proizvodnye.

Absorption and magnetic circular dichroism spectra of nonequilibrium states of hemoglobin and its derivatives formed by reduction oxidased forms of hemoproteins by thermalysed electrons at 77 degrees K were studied. Mixtures of low spin and high spin ferroforms were observed for nonequilibrium hemoglobin and its complexes with inosithexaphosphate and fluorine. The content of the high spin form increasing as follows: hemoglobin, complex with inosithexaphosphate, complex with fluorine. Only low spin forms were found for cyanide and azide complexes of hemoglobin reduced at low temperature. The spectral differences of nonequilibrium low spin ferroforms were supposed to be due to the presence of different ligands in the coordination sphere of the heme iron. The alpha-band splitting was observed for the nonequilibrium imidazole complex of hemoglobin. This effect was explained by a lowe-ring of the active centre's symmetry. The temperature relaxation of all nonequilibrium systems was investigated.

Studies on the conformational changes of metalloproteins induced by electrons in water-ethylene glycol solutions at low temperatures. III. Adrenal ferredoxin.

The reduction of adrenal ferredoxin (adrenodoxin) at low temperatures was investigated in order to separate local modifications of the active centre of the protein on its reduction, from the conformational transition which seems to accompany the change of the redox state of the irons; The ESR spectra of the states of the protein, where the reduced active centre is to be found by the "oxidized" conformation of the apoprotein, were obtained. The transition from the states of the protein to the state which occurs on its chemical reduction at room temperature was also investigated. The results of the work support the view that conformational changes in proteins (enzymes) which take place while they are functioning proceed after modifications of the active centres (change of the redox state, adsorption of a substrate, etc.), and are essentially caused by them. Adrenal ferredoxin was the third subject in our studies of the intermediate states of proteins which appear after reduction of their active centres by means of electrons trapped in water-ethylene glycol mixtures at the temperature of liquid nitrogen [1, 2]. In the reduced state, the active centre of the protein has an ESR signal with a g-factor of 1.94 [3, 4] which is convenient for our purposes.