Biomedical subjects

V I Stabrovskaia

Publications and source records attributed to V I Stabrovskaia.

At least 19 recordsLinked to original sources

PubMed1991

[The nature of the changes in the activity of water-soluble enzymes in action on the muscles of damaging agents. VI. Glyceraldehyde-3-phosphate dehydrogenase binding and enzyme adsorption by F-actin in ghost muscle fiber].

A possibility of binding glyceraldehyde-3-phosphate dehydrogenase (GAPhDG) in frog (Rana temporaria L.) skeletal muscles was studied by measuring its solubilization in 0.15 M KCl and by its presence in isolated actomyosin. Using a 0.15 M KCl solution, more GAPhDG was extracted from intact muscles and muscles treated with heat at 38, 42 and 46 degrees C for 15 min than in a non-electrolyte medium. Actomyosin isolated from muscles reveals GAPhDG activity which cannot be removed by actomyosin reprecipitation. In myosin-, troponin- and tropomyosin-free single glycerinated muscle fibres (ghost fibres) GAPhDG absorption to F-actin was shown. It is suggested that under thermal injure of muscle cells, the increase in GAPhDG binding with thermolabile proteins of actomyosin complex may occur.

Actins↗

PubMed1989

[The nature of changes in the activity of water-soluble enzymes during the action of injurious agents on the muscles. V. A study of the extractability of lactate dehydrogenase from intact and altered muscles].

A study was made of lactate dehydrogenase (LDH) extractability from intact and thermally injured muscles of Rana temporaria L. in the 0.15 M KCl solution and in the non-electrolyte medium. A 15 minute incubation of intact muscles and those treated with heat at 38, 42, 44 and 46 degrees C in the 0.15 M KCl solution led to a much higher extraction of LDH than in the non-electrolyte medium. Following heating at 38 degrees C, causing irreversible injury of muscles, the LDH extractability in the non-electrolyte medium is seen to fall, whereas in the 0.15 M KCl solution it remained at the same level as after LDH extraction from intact muscles. The decrease in LDH extractability in non-electrolyte medium from thermally injured muscles may be due to the increase in LDH binding with thermolabile structural components of muscle. One of the components of muscle cell, known to bind LDH, is actomyosin, since it is isolated from muscles together with LDH, which cannot be removed by actomyosin reprecipitation or by increasing the volume of washing solution.

Actomyosin↗

PubMed1988

[Interaction of the enzymes of cellular energy support with the F-actin of the thin filaments of muscle fiber. I. The binding of lactate dehydrogenase with F-actin induces changes in the structural state of the components of the complex].

A study was made of changes in F-actin conformation occurring in a myosin-free single ghost fibre induced by the binding of glycolytic enzyme lactate dehydrogenase (LDG) to F-actin. The formation of the complex between LDG and F-actin induces changes in the parameters of the intrinsic (tryptophan) and extrinsic (rodominil--phalloin) polarized fluorescence of F-actin of the ghost muscle fibre. It is found that LDG stimulates Mg2+-ATPase of actomyosin in solution. It is assumed that the coupling of energy-providing mechanism with that of muscle contraction may be accomplished through the conformation changes in F-actin.

Actins↗

PubMed1986

[Nature of the changes in the activity of water-soluble enzymes in exposure of muscles to harmful agents. IV. The study of hexokinase extractability from intact and altered muscles].

A possibility of hexokinase binding with actomyosin in skeletal muscles of Rana temporaria L., and the effect of thermal alteration (15 min at 36, 37, 38, 40 and 42 degrees C) on the binding were studied. Solutions of KCl (0.075 M and 0.15 M) extract more hexokinase from intact and altered muscles than does an non-electrolyte medium. Hexokinase freely dissolved in hyaloplasm is extracted in non-electrolyte medium. Hexokinase bound with structural components of the muscle cell is extracted upon the increase in ionic force of the extractant. The solubilizing effect of electrolytes on hexokinase is higher in alterated muscles than in the intact muscles indicating the increase in hexokinase binding under thermal alteration. Actomysin isolated from muscles reveals hexokinase activity. In reprecipitated actomyosin, the larger part of its hexokinase remains in actomyosin gel, the level of hexokinase activity not depending on the number of reprecipitation procedures or on the volume of washing solution. Hexokinase in actomyosin gel is less stable to the thermal action than in water supernatant of muscle extract. This may be due to the increase in hexokinase binding with actomiosin whose sorption activity increases under the thermal denaturation.

Actomyosin↗

PubMed1984

[Changes in hexokinase activity during muscle alteration].

Changes in extractability and activity of hexokinase (HK) were studied under the action of heating and of urea on skeletal muscles of Rana temporaria L., and besides the stability of this enzyme in muscle extract to those agents in vitro was examined. Under a 15 minutes heating of muscle, a decrease in extractability (the activity calculated for 1 g of tissue) and activity (the activity calculated for 1 mg of protein) of hexokinase is first revealed at 37 degrees C. Then the enzyme extractability decreases gradually in accordance to the decrease in extractability of the total water-soluble protein; the level of hexokinase activity attained at 37 degrees does not change up to 40 degrees. At 42 degrees the activity of the enzyme is completely inhibited. Under the heating of the muscle extract, the decrease of enzyme activity takes place at 36 degrees, the level achieved being stable up to 42 degrees C. Under the action of urea on the muscle at the reversible phase of alteration (1 M urea from 5 minutes to 2 hours at room temperature, 1 M urea for 9 hours at + 4 degrees C), hexokinase activity increases, calculated for 1 g of tissue and for 1 mg of protein. Under the irreversible disappearance of muscle excitability (1 M urea during 9 hours, 2 M urea during 2 hours at room temperature) no hexokinase activity was revealed. The activation of the enzyme is discussed in connection with the data on the increase of ATP content in muscle under the urea alteration. The treatment of the enzyme in muscle extract with 1 M urea decreases its activity in 30 minutes down to 67%; the level achieved does not change during 20 hours.

Aerobiosis↗

PubMed1983

[Nature of the changes in the activity of water-soluble enzymes as affected by noxious agents acting on the muscles. I. A study of the extractability of phosphofructokinase from intact and altered muscles].

Binding of phosphofructokinase (PPK) in intact and thermally altered (15 minutes at 38 degrees C) skeletal muscles of frogs (Rana temporaria) the the extractability of PPK from muscles was studied. PPK activity in actomyosin was also studied. Inhibiting effect of electrolytes (KCl, NaCl, CaCl2, MgCl2) on PPK in muscle extract does not allow to use them for the decision of the question of the interprotein interactions of PPK. 5 mM Na2-EDTA extracts additional PPK from homogenates of intact and altered muscles in comparison with PPK extracted in the media without Na2-EDTA (for intact muscles and altered muscles--509 and 729%). Under alteration of muscle, the binding of PPK increases. Among the structural components of muscle which bind PPK, proteins of actomyosin complex have been found.

Actomyosin↗

PubMed1983

[Nature of the changes in water-soluble enzyme activity in the action of injurious agents on the muscles. II. The change in the extractability of aldolase from muscles exposed to urea].

A study was made of solubilization of aldolase isolated from homogenates of skeletal muscles, both intact and being in the state of contracture due to urea action. Compared to water, electrolytes extract more aldolase from homogenates of intact and altered muscles. Almost the same amounts of aldolase were extracted with electrolytes from homogenates of muscles, which lost irreversibly their excitability, and of intact muscles. The actomyosin isolated from muscles displayed aldolase activity not removed under reprecipitation. The aldolase activity of actomyosin, the increase in sorption activity of proteins due to their conformational changes, and the decrease in excitability of aldolase isolated from homogenates of altered muscles by urea doses inducing denaturation of actomyosin and aldolase, all this may suggest that the action of injured agents on muscle stimulates the ability of aldolase and actomyosin to interact. The ratio of free and bound forms of aldolase differs in the intact and in the altered muscle cell.

Actomyosin↗

PubMed1983

[Nature of the changes in water-soluble enzyme activity in the exposure of muscles to harmful agents. III. A study of creatine kinase extractability from intact and altered muscles].

Binding of creatine kinase (CrK) in intact and thermally altered (15 minutes at 37 and 38 degrees C) skeletal muscles of frogs (Rana temporaria L.) was studied according to CrK extractability from muscles. The CrK activity in actomyosin isolated from muscles and its changes in thermally altered actomyosin were detected. Solutions of KCl (0.075, 0.15, 0.3 and 0.6 M) and of NaF (0.15 M) extract additional amounts of CrK from intact and altered muscles. Inhibiting effects of KCl, NaF and K2HPO4 on CrK in muscle extract were found. The latter exerts the most pronounced inhibiting effect, which prevents it from being used for CrK extraction purposes. Among the structural components of muscle that bind CrK actomyosin was detected. The actomyosin isolated from muscles revealed CrK activity. CrK in actomyosin gel is much more stable to thermal effect than that in a water extract of muscle. Such a thermostabity of CrK within the system of the whole muscle cell may apparently result from its being bound to actomyosin.

Actomyosin↗

PubMed1981

[State of the contractile apparatus in the development of a pathological process in muscle. IV. Effect of Ca2+ on the process of contraction nodule formation and on the ATPase activity of muscle actomyosin in Zenker's necrosis].

Using phase-contrast and polarized ultraviolet (UV) fluorescent microscopy, the structure of single muscle fibres was studied in the course of the contraction module formation during Zenker's necrosis. The degree of manifestation of destructive changes in the contractile system was shown to depend upon the concentration of extracellular Ca-ions. With decreasing Ca2+ concentration, the fibre loses the ability to form contraction nodules peculiar to the Zenker necrosis, and the development of this process is interrupted at the stage of sarcomere supercontraction. The UV fluorescent anisotropy pattern of fibre regions, conforming with the contraction nodules, suggests the occurrence of a more pronounced disorganization of contractile system in the presence of Ca2+. The ATPase activity of actomyosin isolated from altered muscle was studied to appreciate the functional state of the contractile system. This actomyosin was found to be inactivated 1.5 times as much as that isolated from muscles treated during Zenker's necrosis in calcium-free media.

Actomyosin↗

PubMed1981

[Changes in phosphorylase activity during muscle alteration].

Changes in the extractability, and in the activity and ratios of active and inactive forms of phosphorylase (PhL) were studied under the action of heating and of urea on skeletal muscles of Rana temporaria L., and under the electric stimulation of the muscle. Besides, the action of these factors on the isolated enzyme was studied. Under the alteration of muscles due to heating, a decrease in extractability and in the activity of the whole PhL takes place. The isolated PhL is more thermostable than that in the intact muscle. Under the action of urea, a decrease in extractability and activity of the whole Phl occurs only with doses of urea which cause the irreversible alteration of muscle. In respect to urea stability, PhL in isolated state is one of the most labile enzymes of the water-soluble fraction. Under contractures produced by the action of heating and of urea, no transformation of an inactive PhL (PhL b) into the active PhL (PhL a) was revealed in the muscle. Under the tetanic contraction produced by the electric stimulation of muscle, a 2.5--3.0-fold increase of PhL a activity takes place under the invariable level of the whole PhL activity.

Animals↗

PubMed1980

[Changes in phosphofructokinase activity upon exposure of muscles and muscle extracts to injurious agents].

A study has been made on changes of outflux, extractability and activity of phosphofructokinase (PPK) under the action of heating, and of urea on the frog's skeletal muscles and on their extracts. Under the action of heating on muscles, the decrease of PPK activity (to 35%) is first revealed 34--36 degress C, when decrease of excitability and the contracture are not yet detected, and the extractability of the total water-soluble protein does not change. At the start of contracture, and at the decrease of excitability (at 38 degrees C) PPK in the muscle loses its activity. The thermolability of PPK is the greatest one compared to all the enzymes investigated before. The data on the high thermolability of PPK are discussed in terms of the regulating role of PPK in glycolysis. The PPK activity of extracts of muscles altered by urea, during the action not accompanied by the death of muscles, does not change. At the irreversible disappearance of muscle excitability, PPK is inactivated. PPK in the cell is more stable to injuring agents than PPK in isolated state.

Adenosine Triphosphate↗

PubMed1978

[Changes in lactate dehydrogenase and glucose-6-phosphate dehydrogenase activity in the course of muscle alteration].

Changes of outflux, extractability and activity of lactate dehydrogenase (LDG) and glucose-6-phosphate dehydrogenase (G-6PhDG) of muscles under the action of heating (at 32--44 degrees for 15 min) and urea (1 M during 10 min, 30 min, 2 hr. and 9 hr.) on the skeletal muscles of R. temporaria L. were studied. Under the thermal action not accompanied by contracture and fall of the excitability (32--36 degrees), the increase of outflux of LDG out of muscles into surrounding solutions is observed. G-6-PhDG in the external medium under any heating action was not revealed. Extractibility of LDG and G-6-PhDG did not change. Under the thermal action accompanied by the fall of excitability and by the contracture, along with the prolong increase of outflux of LDG, a decrease of extractability of LDG takes place. The decrease of G-6-PhDG is set at 42 degrees. Under the alteration of muscles by urea in the period of the temporary fall of excitability and contracture (10 and 30 min) an increase of the outflux of LDG out of muscles is observed. G-6PhDG in the surrounding medium was not revealed up to 9 hr. of incubation of muscle. In the period of the recovery of the excitability and relaxation of muscles (2hr.) the outflux of LDG approaches the control level. During the temporary loss and recovery of excitability, the extractability of LDG and G-6-PhDG does not change. In the period of irreversible contracture and loss of the excitability (6--10 hr.) a sharp increase of outflux of LDG out of muscles takes place. The extractability of the examined enzymes, especially of LDG, decreases.

Animals↗

PubMed1977

[Changes in aldolase and creatine kinase activity during thermal muscle damage].

A study was made of changes in outflux, extractability and enzyme (aldolase and creatine kinase) activity of muscle proteins induced by thermal action in skeletal muscles of R. temporaria L. Under a 15-minutes action of temperatures under 36 degrees C, which do not produce any contracture or fall of excitability, changes in a fraction of protein outfluxed from muscles were observed. The thermal action accompanied by the fall and irreversible loss of excitability (above 36 degrees) resulted in the fall of extractability and enzyme activity of water-soluble proteins extracted from homogenized muscles in addition to prolonged changes in the fraction of outfluxed proteins. The increased binding of aldolase by actomyosin under thermal injury of muscle is established. Changes of outflux extractability and enzyme activity of proteins during the thermal alteration of muscle are considered with regard to data about the complexing of muscle proteins.

Animals↗

PubMed1976