Showing papers in "Ukraïns'kyĭ biokhimichnyĭ zhurnal in 1976"

Effect of carnosine and anserine on excitation and contraction of fatigued skeletal muscle

Abstract: The effect of dipeptides (carnosine and anserine) on a neuromuscular preparation under fatigue or diplacine blocking is shown to result in a significant restoration of the muscle contraction. The analysis of this phenomenon evidences that synaptic processes are not responsible for the restoration, at least under the given experimental conditions. At the same time, the absence of any effect of the compounds studied on the maximal rate of isotonic shortening and on the tension of glycerinized fibres and ATPPase of native and desenitized actomyosine indicates that the contractile mechanism is not involved in the effect described. On the other hand, the dipeptides restore the value of the transmembrane potential depolarized by exhaustion, increase the amplitude of isometric twitch and the value of maximal load under isotonic conditions. Moreover, the time of the contractile cycle in the presence of the dipeptides is considcted to the processes of electromechanical coupling in skeletal muscles.

Anticlotting activity of fragment D from fibrinogen and fibrin and its dependence on calcium presence when fragments are obtained from fibrinogen

Abstract: The CaCl2 concentration of about 10(-4) M slightly reduces the proteolytic fibrinogen degradation and greatly increases the anticlotting activity in the arising fragments D. With a rise in the CaCl2 concentration to 10(-2) M a subsequent limitation of proteolysis occurs, but less active fragments D are formed. These facts suggest that a moderate restriction of peptide bond cleavage enhances the fragment D activity, whereas excessive restriction exhibits an adverse effect. Fragment D originating from noncross-linked fibrin inhibits clotting stronger than its counterpart--the fibrinogen derivative. The following explanation seems plausible. Certain sites of the intact molecules, essential for the inhibitory activity of the prospective fragment D, become somewhat "enzyme-proof" (due to intermolecular links characteristic of polymeric fibrin), thus, avoiding proteolytic damage. Calcium ions presented at the optimum concentration may act similarly.

[Peculiarities of acid-base reserves in aging].

Abstract: The age-dependent peculiarities of the acid-base balance at rest and with standard loads were studied in 466 rats. It was found that with age the pH value of blood decreases, the tension of the carbonic acid increases, but the values of BB, BE, SB, and AB do not undergo any significant changes. With loads, old animals showed more profound changes in the system and these changes were of decompensated character. The maximal changes in young animals were registered 1.5 hours after loading, in old rats--3 hours after. The normalization of the shifts in old rats occurred much more slowly than in young animals, and it does not reached the initial value by 24 hours after loading. The analysis of the data obtained shows that with aging the reserve potentialities of the organism's mechanisms of the acid-base balance regulation greatly decrease, which under certain conditions results in disturbance of the given system compensation, thus exerting a negative effect on the body vital processes.

[Heterogeneity of neurospecific protein S-100]

Abstract: Protein S-100 specific for the nervous system was isolated from the bull cerebral hemispheres by the Steward method and antiserum monospecific to it was obtained. In immunoelectrophoretical study of the initial brain extract with antiserum detected the paired line of precipitation consisting of two arcs in the zone of prealbumins and alpha2-globulins of the the serum, and that with purified protein fraction showed only one arc corresponding to the prealbumin component. The purified protein S-100 fraction in agar gel is divided into a series of prealbumin electrophoretic zones, with a pre-protein locating chiefly in the most mobile zone. It is established that heterogeneity of protein S-100 with electrophoresis in agar gel and immunophoresis is due to the presence of calcium ions in the systems. In the presence of 1 mM EDTA solution the one or two closely located prealbumin zones of purified protein S-100 migrates. The obtained monospecific antiserum made it possible to establish that two-fractional antigen A detected previously by the heterogenic antisera is protein S-100.

[Effects of UV-radiation of different spectral composition on content of sterols in rat skin].

Abstract: When irradiating rats with sources of UV-radiation of different spectral composition a decrease in a relative content of cholesterol is found in the animal skin. Simultaneously an increase in the content of such cholestorol biosynthesis precursors as lathosterol and 7-dehydrocholesterol is observed. The formation of cholesterol photooxidation products under the effect of UV-radiation in vivo is shown. The quantitative ratios of sterols under study depend on spectral characteristics of the applied UV-radiation sources. The cholesterol photooxidation products and antirachitic compounds formed in skin under the effect of UV-radiation are supposed to take part in inhibition of cholesterol biosynthesis.

Action of acid cathepsins on the myosin and sarcoplasmic proteins of normal and denervated rat muscles

Abstract: The activity of acid cathepsins in extracts of the healthy and denervated rat muscles was determined, using the proper and homologous sarcoplasmic proteins and myosin as substrates. Splitting of the sarcoplasmic proteins produces a 50% increase and that of myosin produces a 110% increase in the activity of acid cathepsins of the denervated muscles as compared to that of healthy ones. Substrates isolated from the healthy and denervated muscles are splitted by acid cathepsins with the same intensity.

[Activity of carbohydrate-metabolizing enzymes and content of carbohydrate and nitrogen compounds in muscles of young cattle depending on breed and sex].

Abstract: The activity of glycolysis and glyconeogenesis enzymes, content of carbohydrate and nitrogen compounds were studied in muscles of 15-month cattle of different sex of the black-piebald breed and its crosses with bulls of two meat breeds Hereford and Limousine. In the muscles of bulls the activity of phosphoglucomutase, phosphohexoisomerase, aldolase and fructose-1,6-diphosphatase is considerably higher (except of the activity of phosphoglucomutase and phosphohexoisomerase in the muscles of pure-bred black-piebald animals for which difference is not statistically reliable) and the content of glycogen, glucose, fructose, lactic acid, free and phosphorylated pentoses of nonadenylic compounds is essentially lower than in the muscle tissue of heifers of analogous breed groups. A higher activity of carbohydrate metabolism enzymes (especially aldolase and fructose-1,6-diphosphate) and a higher content of total pentoses, the adenylic system pentoses, ATP phosphorus in the muscles of the cross Limousine and Hereford bulls and Limousine heifers as compared to the pure-bred black-piebald animals of the corresponding sex coincide with a greater increase in the muscular tissue and more intensive synthesis of proteins in it. A considerably lower level of glycogen, glucose, fructose and a relatively high activity of carbohydrate metabolism enzymes in the muscles of cross young cattle show that disintegration of these carbohydrates is in excess of their synthesis, that is due to an increase in the energy demand connected with a more intensive synthesis of proteins in the muscular tissue. Therefore, in the authors opinion the performed kill of the cross Limousine and Hereford bulls as well as Limousine heifers, is somewhat untimely and unreasonable. At the same time the activity of all the studied enzymes in the muscles of the cross Hereford heifers, vice versa, is considerably lower as compared to the black-piebald heifers and coincides with a low gain in live weight and muscular tissue, a more rapid accumulation of glycogen and lipids and a more delayed--of proteins in the muscular tissue, that evidences for their early maturity. Therefore the further raising of the cross Hereford heifers in the farm for obtaining meat is economically less profitable. The data obtained give grounds to recommend determination of the activity of carbohydrate metabolism enzymes, especially of aldolase and fructose-1,6-diphosphate, as a test for checking the muscular tissue growth and for prognosing the meat productivity in the growing pure-bred and cross young cattle of different sex.

Glutathione peroxidase and glutathione reductase activity in the rat liver after the administration of sodium selenite

Abstract: Sodium selenite 24h after its single administration to rats causes an increase in the activity of glutathione peroxidase and glutathione reductase in the liver tissue. 6 h after the selenium administration the enzymes activity does not differ from the control. Doses of 0.15, 0.3, 0.5 and 1 mg of selenium per 1 kg of the animal weight were investigated. 0.3 mg proved to be the least effective dose. An increase in the enzyme activity after administering 0.5 mg of selenium is retained for 6 days and 14 days after it does not differ from the control. The liver relative weight 24 h after administration of 0.5 mg of selenium per 1 kg of animal weight proved to be higher but three days later it did not differ from the control. After administering selenium in a dose of 1 mg/kg the liver relative weight was higher for 6 days. Actinomycin D administered in a dose of 0.5 mg/kg simultaneously with selenite prevents the rise in the enzyme activity and relative weight of the liver caused only by a single injection of selenium in the same dose.

Effect of heparin on oxidative phosphorylation and ultrastructure of rabbit heart mitochondria

Abstract: The effect of heparin on isolated rabbit heart mitochondria was studied in usual clinical (0.25 u/ml) and higher doses. Hepain concentration 0.25 u/ml stimulated respiration in the state 4, decreased ADP/O ratio and phosphorylation rate and did not affect mitochondria ultrastructure. Higher concentration caused two-phase changes in respiration-short-time stimulation with the following inhibition, oxidative phosphorylation (respiratory control, ADP/O, phosphorylation rate) was progressively depressed and decoupled. The mitochondria ultrastructure is changed under the influence of 1.25 u/ml and of higher doses; the external membrane lost its two-layer character, the crista were converted into a small granular mass. Concentration of 1.25 u/ml transformed many mitochondria into empty vesicles.

[Isolation of Na+, K+-ATP-ase].

Abstract: The data are discussed on the isolation of Na+, K+-ATPase from the membrane structures of a cell at functionally active state The isolation of the membrane enzymes, particularly multicomponent enzymic systems, which might include Na+, K+-ATPase, is a rather complex task as their components are ordered in the membrane in a certain way The disturbance of this ordering that is essentially maintained by membrane phospholipids, results in the inactivation of the enzymatic system Different procedures are compared permitting the Na+, K+ATPase isolation and purification to be realized It is noted that when realizing the Na+, K+-ATPase isolation and purification by means of a number of non-ionic detergents it is possible to obtain the "soluble" Na+, K+-ATPase preparations from the membrane structures, the preparations being a convenient initial material for the further purification of this enzymic system and its obtaining as a "functionally intact unit" The Na+, K+-ATPase isolation as a "functionally intact unit" would probably make an essential contribution to deciphering the molecular mechanism of the Na+ and K+ transport through biomembranes

[Effect of glucocorticoid hormones on nuclear RNA-polymerase activity and RNA metabolizability in rat skeletal muscles].

Abstract: It has been found that in hypercorticism induced by a prolonged ACTH administration when protein synthesis is inhibited in the skeletal muscles the incorporation of Na2HP32O4 into muscle RNA intensifies by 30% and the RNA-polymerase activity of muscle nuclei is approximately twice as high. In the adrenalectomized rats 3 hours after a single hydrocortisone administration a sharp rise in the RNA-polymerase activity of the skeletal muscle nuclei is observed as well. Such an increase in RNA synthesis is suggested to be a response to the inhibition of protein synthesis through feedback mechanisms.

Role of muscle pyruvate dehydrogenase histidine residues in thiamine pyrophosphate binding

Abstract: The interaction of diethylpyrocarbonate (DEP) with the pyruvate dehydrogenase component (PDH) isolated from the pyruvate dehydrogenase complex (EC 1.2.4.1) results in a modification of 3-5 histidine residues per mole of enzyme, which simultaneously decreases the enzyme activity. After PDH inhibilion by DEP in the presence of dithiothreitol almost complete reactivation (94%) under the effect of neutral hydroxylamine is observed. In the absence of SH-groups protection incomplete reactivation by hydroxylamine (79%) is found. In the latter case titration with 5,5-dithio--bis-(2-nitrobenzoic acid) in 8 M urea showed that the DEP-modified protein contains less quantity of SH groups (by 4-8) as compared to the native enzyme. It is assumed that the DEP-modified SH-groups are not responsible for the enzyme activity. The differential spectrum of the modified and native PDH showed no changes within the range of 260-300 nm. TPP in combination with Mg2+ (10(-3) M) protectes PDH from being inactivated by DEP. TPP (10(-2) M) reactivates PDH by 70% after its complete inhibition by DEP. Similar protective action is manifested by ATP, ADP and inorganic pyrophosphate in the presence of Mg2+. A kinetic study showed a competitive type of PDH inhibition by DEP with respect to TPP. it is concluded that the histidine residues of PDH are involved in TPP binding.

[Structural peculiarities of protein typical of G-myelomas].

Abstract: G-myeloma protein is shown to differ by its conformation from the donor immunoglobulin G. It is characterized by a more polar surrounding of the molecule tyrosine and tryptophane residua. Under the effect of urea the changes are less considerable.

[Effect of thiol-oxidizing agents on several enzymes in rat liver mitochondria].

Abstract: The sulphydryl groups of nonprotein thiols and proteins of mitochondria, activity of enzymes, oxidative phosphorylation and swelling of these organellas were studied as affected by the thiol-oxidizing agents. Diamide and azoester are shown to oxidize SH-groups of mitochondria, inhibit isocytrate dehydrogenase and succinate: cytochrome oxidation and inhibits energy-dependent swelling of mitochondria. Under the effect of azoester the rate of oxygen consumption by mitochondria increases and there occurs their sharp swelling.

[Effect of C-4'-modification of thiamine pyrophosphate on its coenzyme activity in the oxidative decarboxylation of pyruvic acid reaction].

Abstract: Interaction was studied between pyruvate dehydrogenase (EC 1.2.4.1) and C-4'-substituted analogs of thiaminpyrophosphate, 4'-N (CH3)-TPP, 4'-N(CH3)2-TPP and OH-TPP. None of these analogs was found to replace TPP during the reduction of NAD and 2.6-dichlorophenol-indophenol as well as pyruvate decarboxylation. The decarboxylase activity of the pyruvate dehydrogenase component isolated from the pyruvate dehydrogenase complex was determined according to the 14CO2 yield and production of 2-C-oxoethyl-TPP using 1-14C-pyruvate and 2-14C-pyruvate, as substrates, respectively. All the analogs were found to competitively inhibit pyruvate dehydrogenase, Ki values for 4'-N(CH3)-TPP, 4'-N(CH3)2-TPP and 4'-OH-TPP being 4.1 X 10(-5) M, 8.5 X 10(-5) M and 2.9 X 10(-6) M, respectively; Km values for TPP was equal to 1-2 X 10(-7) M. It is assumed that the analogs of the holoenzymic complex formed by the pyruvate dehydrogenase component of the pyruvate dehydrogenase complex with mono-, dimethyl-TPP and oxo-TPP do not bind the substrate.

Glutathione peroxidase and glutathione reductase activity in rat liver following administration of vitamin E and methionine

Abstract: A single introduction of vitamin E and D,L-methionine to rats kept on the vivarium ration or their addition to protein-free diet separately does not affect the glutathionperoxidase and glutathionreductase activities in the liver. A simultaneus introdyction of the vitamin and methionine causes an increase in the glutathionperoxidase activity, without changing the glutathionreductase activity. Vitamin E prevents from increasing the glutathionperoxidase and glutathionreductase activities due to selenium. Propyl gallate produces no such effect.

[Electrophoretic fractions and NH2-terminal amino acids of high-molecular tryptic fragments of fibrinogen and fibrin].

Abstract: The electrophoretic and NH2-terminal analyses were performed for D and E fragments obtained by tryptic digestion of bovine fibrinogen and fibrin under various conditions. The preparations of fragment D were heterogeneous, they were separated by polyacrylamide gel electrophoresis into a number of electrophoretic components with molecular weight ranging from 65 000 to 85 000. NH2-terminal analysis revealed from 6 to 8 NH2-terminal amino acids: Ser, Gly, Thr, Asp, Gly, Lys, Gln, Asn. Their composition and quantitative ratios were found to vary depending on the conditions of the fragment D production. The electrophoregrams showed that with Ca++ in the medium the enzymatic splitting of fibrinogen was limited. Fragment D obtained from fibrinogen without Ca++ was electrophoretically rather similar to that obtained from fibrinogen at Ca++ optimal concentration. Taking into consideration a very high specific anti-coagulational activity of these two fragment D preparations, one may conclude that both the polymerized state of protein molecules and the presence of Ca++ stabilize the specific molecular structure, that favorus the preservation of specific inhibitory activity in fragment D. According to the NH2-terminal analysis data, fragment E derived from fibrinogen hydrolyzed in the presence of Ca++ optimal concentration is also heterogeneous. The following amino acids were found: Tyr, Lys, His (main ones) and Gly, Ser, Thr, Val (minor ones). As to molecular weight determined by electrophoresis, fragment E appears to be homogeneous.

ATPase activity of subcellular rat brain fractions following hyperoxia

Abstract: The total Mg2+-ATPase and Na+, K+-ATPase activity was studied in the fractions of "400 g X for 20 min" and "900 g X for 30 min" conditionally called the fraction of the external cellular membranes and total fraction of mitochondria. The subcellular fractions were isolated from great hemispheres and stem part of the rat brain. The brain of control animals and those during a severe spasmodic attact induced by the oxygen action at a pressure of 6 ati was studied. The total ATPase activity is established to be practically the same in the studied brain areas and unchanged with hyperoxia. Hyperoxia accompanying by convulsions results in an increase in the activity of Mg2+-ATPase and in a decrease in that of Na+, K+-ATPase both in the cerebral cortex and the stem part. The authors suppose that the decrease in the enzyme activity may occur due to an inhibitory effect on it of the lipids reoxidation products formed in the brain with hyperoxia.

Differences in the enzymatic activity of mitochondria from enriched neuronal and glial fractions

Abstract: Studies were performed in the activities of certain enzymes from oxidoreductase group: cytochrome c-oxidoreductase (EC 1.6.99.3), succinate dehydrogenase succinates: cytochrome c-oxidoreductase (EC 1.3.99.1), cytochrome oxidase (EC 1.9.3.1) and malate dehydrogenase (EC 1.1.1.37) in mitochondria from neuronal and glial-enriched fractions. The mitochondrial fraction purity was observed by the electron microscope. The enzyme activity of the glial mitochondrial fraction was much higher than that in the neuronal mitochondria. Malate dehydrogenase from glial enriched fraction consists of three isoenzymes, while neuronal mitochondria had two isoenzymes of malate dehydrogenase. The neuronal mitochondria were found to be more stable to lubrol and digitonin.