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1.
Chem Phys Lipids ; 62(3): 229-37, 1992 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-1468123

RESUMO

It is shown that cholesterol may interact with some substances containing the guanidine group (guanidine itself, arginine, metformin and dodecylguanidine bromide) and with arginine-rich proteins--apoproteins A-I and E. In the latter case the interaction produces the formation of cholesterol-apoprotein complexes. Analysis of such complexes has shown that one apo A-I molecule binds 17-22 and one apo E molecule binds 30-35 sterol molecules, which approximately corresponds to the amount of arginine residues in these proteins. Formation of cholesterol-apoprotein complexes has been suggested to occur due to: (1) formation of hydrogen bond and/or ion-dipole interaction between cholesterol hydroxyl and guanidine groups of the apoprotein arginine residues and (2) hydrophobic interaction of the cholesterol aliphatic chain with nonpolar side chains of the amino acids occupying the third position from arginine in the protein molecule.


Assuntos
Apolipoproteína A-I/metabolismo , Apolipoproteínas E/sangue , Colesterol/metabolismo , Sequência de Aminoácidos , Animais , Apolipoproteína A-I/química , Apolipoproteínas E/química , Arginina/química , Sítios de Ligação , Colesterol/química , Humanos , Hipercolesterolemia/sangue , Dados de Sequência Molecular , Rotação Ocular , Ligação Proteica , Estrutura Secundária de Proteína , Coelhos , Espectrofotometria Ultravioleta
2.
Mol Biol (Mosk) ; 18(2): 404-9, 1984.
Artigo em Russo | MEDLINE | ID: mdl-6717420

RESUMO

The ability of some proteins to bind cholesterol was accompanied by a decrease of turbidity of aqueous cholesterol suspensions and correlated with a quantity of arginine residues in them. Maximum clearing of aqueous cholesterol suspensions at the addition of proteins containing equimolar arginine concentrations was observed in the presence of apoproteins E and A-I. Optical rotatory dispersion spectra of apoprotein E, polyarginine and histone H3 have shown the influence of sterol on the secondary structure of apoprotein E only.


Assuntos
Apolipoproteínas/análise , Proteínas de Transporte/análise , Colesterol/metabolismo , Apolipoproteínas/metabolismo , Apolipoproteínas E , Arginina/análise , Proteínas de Transporte/metabolismo , Histonas/análise , Conformação Proteica , Espectrofotometria
3.
Ukr Biokhim Zh (1978) ; 61(5): 29-34, 1989.
Artigo em Russo | MEDLINE | ID: mdl-2555950

RESUMO

Cholesterol was studied in experiments in vitro for its effect on the activity of Na, K-ATPase of the synaptic brain membranes of rats and a crystalline preparation of glutamate dehydrogenase from the liver mitochondria of a bull. Cholesterol decreased the activity of the above enzymes. When blocking guanidine groups of arginine residues of Na, K-ATPase and glutamate dehydrogenase the inhibiting action of cholesterol was absent. The obtained data evidence for the possibility of a direct interaction of cholesterol with membrane enzymes as well as for the important significance of guanidine groups of arginine residues of proteins in the process.


Assuntos
Arginina/metabolismo , Colesterol/metabolismo , Glutamato Desidrogenase/metabolismo , Guanidinas/metabolismo , ATPase Trocadora de Sódio-Potássio/metabolismo , Animais , Encéfalo/enzimologia , Bovinos , Guanidina , Masculino , Mitocôndrias Hepáticas/enzimologia , Ratos , Membranas Sinápticas/enzimologia
4.
Ukr Biokhim Zh (1978) ; 61(3): 42-7, 1989.
Artigo em Russo | MEDLINE | ID: mdl-2749912

RESUMO

It is established in the in vitro experiments that subfraction of HDL3 is able of accepting cholesterol from the atherosclerosis-afflicted aorta intima. Apoprotein E has no effect on the acceptance of cholesterol from the intima by HDL3 particles. The role of the protein under its joint incubation with the aorta intima and HDL3 is reduced to the uptake of cholesterol esters from HDL3-particles enriched by cholesterol. It is assumed that apoprotein E under certain metabolic conditions can transfer esterified cholesterol from HDL-particles on other lipoproteins as well as into tissues impoverished in the cholesterol content.


Assuntos
Apolipoproteínas E/fisiologia , Ésteres do Colesterol/metabolismo , Aorta/metabolismo , Aorta/fisiologia , Arteriosclerose/metabolismo , Arteriosclerose/fisiopatologia , Transporte Biológico , Centrifugação com Gradiente de Concentração , Humanos , Técnicas In Vitro , Lipoproteínas HDL/fisiologia
5.
Vopr Med Khim ; 23(5): 658-61, 1977.
Artigo em Russo | MEDLINE | ID: mdl-595502

RESUMO

A time-consuming procedure of isolation of pyruvate kinase isoenzymes from rabbit kidney cortex (more than 5 hrs) at 0-2 degrees led to obtaining of a desensitized form of "L" type, resembling the "M3" type of the enzyme from sceletal muscle. Rapid isolation of pyruvate kinase "L" type (within about 2.5 hrs) at 4-6 degrees provided the isoenzyme in the active (allosteric) form.


Assuntos
Isoenzimas/isolamento & purificação , Córtex Renal/enzimologia , Piruvato Quinase/isolamento & purificação , Sítio Alostérico/efeitos dos fármacos , Aminoácidos/farmacologia , Animais , Relação Dose-Resposta a Droga , Ativação Enzimática/efeitos dos fármacos , Frutosedifosfatos/farmacologia , Masculino , Métodos , Coelhos , Temperatura , Fatores de Tempo
6.
Vopr Med Khim ; 22(6): 773-8, 1976.
Artigo em Russo | MEDLINE | ID: mdl-1027250

RESUMO

Alloxan diabetes, starvation of rabbits within one day and administration of hydrocortisone during 5 days did not cause distinct alterations in the total activity of pyruvate kinase in kidney cortex. At the same time pronounced alterations in the isozyme spectra were observed: the L-type activity of pyruvate kinase was decreased and the M2-type of activity was increased. The total activity and the isozyme content of pyruvate kinase were only slightly altered in starvation of rabbits during 3 or 10-16 days and after administration of protamine-Zn-insulin during 3 days. Hydrocortisone caused variable effects on the pyruvate kinase isozymes from kidney cortex, depending on periods of administration.


Assuntos
Hidrocortisona/farmacologia , Insulina de Ação Prolongada/farmacologia , Isoenzimas/metabolismo , Córtex Renal/enzimologia , Piruvato Quinase/metabolismo , Animais , Cromatografia DEAE-Celulose , Diabetes Mellitus Experimental/enzimologia , Jejum , Isoenzimas/análise , Córtex Renal/análise , Masculino , Piruvato Quinase/análise , Piruvatos , Coelhos , Fatores de Tempo
7.
Vopr Med Khim ; 21(3): 332-4, 1975.
Artigo em Russo | MEDLINE | ID: mdl-1210112

RESUMO

A decrease in activity of pyruvate kinase by 43% in kidney medulla was observed in rabbits, which lasted for 10-16 days. In kidney medulla of rabbits with alloxan diabetes the pyruvate kinase activity was increased by 39% as compared with control animals.


Assuntos
Diabetes Mellitus Experimental/enzimologia , Insulina/fisiologia , Medula Renal/enzimologia , Rim/enzimologia , Piruvato Quinase/metabolismo , Animais , Jejum , Coelhos
8.
Vopr Med Khim ; 25(2): 171-6, 1979.
Artigo em Russo | MEDLINE | ID: mdl-442588

RESUMO

Activity of M2-pyruvate kinase from medullar layer of rabbit kidney was studied in diabetes, in starvation within 1 day and 10-16 days and in long-term starvation of rabbits after administration of glucose or hydrocortisone and protamine-Zn-insulin. The enzymatic activity was increased in diabetes and decreased in long-term starvation and after administration of insulin. A correlation was observed between low activity of pyruvate kinase in kidney medulla under conditions of long-term starvation of rabbits and deficiency of the enzyme substrate. The data, obtained after study of the enzymatic activity in kidney medulla as compared with that of rabbit kidney cortex, demonstrate various adaptability of cells from these kidney layers to regulatory effects of hormones on the pyruvate kinase activity.


Assuntos
Hidrocortisona/farmacologia , Insulina/farmacologia , Córtex Renal/enzimologia , Medula Renal/enzimologia , Piruvato Quinase/metabolismo , Animais , Diabetes Mellitus Experimental/enzimologia , Isoenzimas/metabolismo , Córtex Renal/efeitos dos fármacos , Medula Renal/efeitos dos fármacos , Masculino , Coelhos , Inanição/enzimologia , Fatores de Tempo
9.
Vopr Med Khim ; 23(5): 653-7, 1977.
Artigo em Russo | MEDLINE | ID: mdl-595501

RESUMO

Ca2 ions showed the various effect on isoenzymes of pyruvate kinase from rabbit kidney cortex. Ca2 activated the "L" type of pyruvate kinase at low concentrations of PEP and inhibited -- at high concentrations of the latter. "M2" type of pyruvate kinase was inhibited by Ca2 under all the conditions studied. In presence of Ca2+ the activating effect of PDP on "L" and "M2" types of pyruvate kinase was absent; the inhibitory action of ATP on the "M" type of pyruvate kinase was increased at all the concentrations above 1.3 mM. The effect of Ca2+ on the pyruvate kinase isoenzymes depended on content of Mg2+ in the medium.


Assuntos
Cálcio/farmacologia , Isoenzimas/metabolismo , Córtex Renal/enzimologia , Piruvato Quinase/metabolismo , Trifosfato de Adenosina/farmacologia , Animais , Cátions Bivalentes , Relação Dose-Resposta a Droga , Frutosedifosfatos/farmacologia , Gluconeogênese/efeitos dos fármacos , Glicólise/efeitos dos fármacos , Córtex Renal/efeitos dos fármacos , Masculino , Manganês/farmacologia , Fosfoenolpiruvato/farmacologia , Coelhos
10.
Vopr Med Khim ; 30(3): 86-90, 1984.
Artigo em Russo | MEDLINE | ID: mdl-6474943

RESUMO

Interaction of cholesterol with apoproteins A-I and E was studied in absence of phospholipids in vitro. As shown by two methods - ultracentrifugation in density gradient of KBr and an extraction technique - an apoprotein E molecule bound 30-35 molecules of cholesterol and a molecule of A-I bound 17-22 molecules of the sterol. If the primary structure of apoprotein A-I and the fragments of apoprotein E are involved in consideration, the hydrophilic reaction appears to occur between the hydroxyl group of cholesterol and a guanidine group of the protein arginine residues as well as hydrophobic reaction - between side aliphatic chain of the sterol and the branched-chain amino acid, present in the protein at a distance of 4 amino acid residues from the arginine residue. A molecular model, illustrating the cholesterol reaction with polypeptide fragments, is developed. Considering high alpha-spirality of apoproteins E and A-I with specific localization of the charged residues, reaction of the sterol and apoproteins, described in the terms of this model, was possible only after a decrease in order of the protein structure. Dispersion spectra and optical rotation of apoprotein E showed that beta-structures were destroyed and alpha-spiralization was decreased in the protein in presence of cholesterol. The data obtained suggest that amino acid composition and structure of polypeptides are important for their reaction with cholesterol.


Assuntos
Apoproteínas , Colesterol , Peptídeos , Sequência de Aminoácidos , Animais , Apolipoproteínas , Apolipoproteínas A , Apolipoproteínas E , Humanos , Ligação de Hidrogênio , Modelos Moleculares , Conformação Proteica , Coelhos
11.
Vopr Med Khim ; 35(4): 43-8, 1989.
Artigo em Russo | MEDLINE | ID: mdl-2815679

RESUMO

Both subfraction "2" of high density lipoproteins (HDL2) from patients with hypo-alpha-lipoproteinemia and subfraction HDL3 from persons with normal content of cholesterol were shown to accept the erythrocyte membranes cholesterol in vitro. Under these conditions HDL3 subfraction was transformed into HDL2-like particles, where content of unesterified cholesterol and its esters was increased simultaneously with enlargement of the particles size. The HDL subfraction, isolated from persons with high content of cholesterol, did not accept cholesterol under the experimental conditions. Apoprotein E, containing in the HDL subfractions, was not responsible for the particles cholesterol-accepting properties. Apoprotein E itself was capable of cholesterol elimination from erythrocytes as well as of cholesterol esters from HDL3 and HDL2-like particles with formation of a specific complex.


Assuntos
Apolipoproteínas E/metabolismo , Colesterol/metabolismo , Hipolipoproteinemias/metabolismo , Lipoproteínas HDL/metabolismo , Membrana Eritrocítica/metabolismo , Humanos , Hiperlipoproteinemias/metabolismo , Lipoproteínas HDL/sangue , Proteínas de Membrana/metabolismo
12.
Biokhimiia ; 40(5): 978-83, 1975.
Artigo em Russo | MEDLINE | ID: mdl-813784

RESUMO

Pyruvate kinase (PK-II) isoenzyme from rabbit adrenal cortex was isolated by chromatography on DEAE-cellulose during long-term incubation in the cold. The enzyme is resistant to fructose-1,6-diphosphate (FDP) and L-alanine. Dithiotreitol and preincubation for 10 min. at 30 degrees C did not change the resistance of the enzyme to these factors. Preincubation for 30 min. at 30 degrees C in the presence of EDTA (3.3 mM) converted the enzyme into the FDP-sensitive form, the dependency curve of the initial reaction rate on the concentration of phosphoenolpyruvate being S-form. Sucrose and dithiotreitol contributed the isolation of PK-II from rabbit adrenal cortex in the form having a higher degree of the interaction of active sites.


Assuntos
Córtex Suprarrenal/enzimologia , Glândulas Suprarrenais/enzimologia , Isoenzimas/isolamento & purificação , Piruvato Quinase/isolamento & purificação , Alanina/farmacologia , Animais , Cromatografia DEAE-Celulose , Ácido Edético/farmacologia , Frutosefosfatos/farmacologia , Fosfoenolpiruvato/farmacologia , Piruvato Quinase/metabolismo , Coelhos
13.
Biokhimiia ; 40(5): 1094-8, 1975.
Artigo em Russo | MEDLINE | ID: mdl-1212447

RESUMO

Pyruvatekinase (PK) isoenzymes were isolated by means of (NH4)2SO4 fractionation (20-45% and 50-70% of saturation) and DEAE-cellulose chromatography. Two peaks of PK activity (I and II) were discovered under chromatography of 20-45% saturation precipitate, and one peak (I-A)-under chromatography of 50-70% saturation precipitate. PK-II in its properties (two-peaks kinetics for phosphoenolpyruvate (PEP), the resistance to effectors) is like L-type PK, which has lost its allosteric properties in the process of long-term isolation at low temperatures. PK-I and PK-I-A have S-form kinetics for PEP. They are inhibited by L-alanine and phenylalanine, and they probably are variants of the initial K(M2) type.


Assuntos
Córtex Suprarrenal/enzimologia , Glândulas Suprarrenais/enzimologia , Isoenzimas/análise , Piruvato Quinase/análise , Alanina/farmacologia , Animais , Cromatografia DEAE-Celulose , Cinética , Fenilalanina/farmacologia , Fosfoenolpiruvato/metabolismo , Piruvato Quinase/antagonistas & inibidores , Coelhos
14.
Biokhimiia ; 45(1): 51-5, 1980 Jan.
Artigo em Russo | MEDLINE | ID: mdl-7213839

RESUMO

Apoprotein E was isolated from delipidated lipoproteins of very low density obtained from blood plasma of rabbits with experimental hypercholesterinemia. The protein, whose molecular weight is 45000, produces a single hand during polyacrylamide gel electrophoresis and contains 10% of arginine. The formation of an apoprotein E -- cholesterol complex and participation of guanidine groups of guanidine groups of arginine residues of apoprotein E in cholesterol binding have been postulated.


Assuntos
Apolipoproteínas , Colesterol , Lipoproteínas VLDL , Animais , Apolipoproteínas/sangue , Lipoproteínas VLDL/sangue , Peso Molecular , Ligação Proteica , Coelhos
15.
Biokhimiia ; 57(4): 555-65, 1992 Apr.
Artigo em Russo | MEDLINE | ID: mdl-1637918

RESUMO

It was shown that cholesterol can interact with some guanidine group-containing compounds (guanidine proper, arginine, metformine and dodecylguanidine bromide) as well as with the arginine-rich proteins--apoproteins A-1 and E. In the latter case this interaction results in the formation of cholesterol-apoprotein complexes. Analysis of such complexes revealed that one apo-A-1 molecule binds 17-22, whereas one apo-E molecule--30-35 sterol molecules, which approximately correspondence to the amount of arginine residues in these proteins. The formation of cholesterol-apoprotein complexes seems to be due to: (1) formation of hydrogen bonds and ion-dipole interactions between the hydroxyl groups of cholesterol and the guanidine groups of the apoprotein arginine residues and, presumably, the carboxylic groups of aspartic or glutamic acids, eventually resulting in the production of chelate complexes; (2) hydrophobic interaction of the cholesterol aliphatic chain with the nonpolar side chains of the amino acids occupying the third position from arginine in the protein molecule.


Assuntos
Apolipoproteína A-I/metabolismo , Apolipoproteínas E/metabolismo , Colesterol/metabolismo , Guanidina , Guanidinas/química , Humanos , Modelos Moleculares , Análise Espectral , Temperatura , Ultracentrifugação
16.
Biochemistry (Mosc) ; 66(3): 300-4, 2001 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11333154

RESUMO

To study the transfer of oxidized phospholipids from cell membranes to high-density lipoproteins (HDL), human Cu2+-oxidized erythrocyte membranes were incubated with HDL3 subfraction for 17 h at 37 degrees C followed by isolation of the supernatant, precipitation from it of HDL3, and determination of lipid peroxide products (LPP) in them. The incubation increased the content of lipid hydroperoxides in HDL3 significantly (by 32 and 40% calculated per ml of sample or mg of protein) and of malondialdehyde (by 27 and 34%, respectively) compared to control (incubation of HDL3 alone). The content of conjugated dienes did not change significantly. Fluorescence analyses of isolated HDL3 particles showed that the content of fluorescent products (lambdaex = 365 nm, lambdaem = 430 nm) in them was 2.5 times higher than in control, and the number of binding sites for the 1-anilinonaphthalene-8-sulfonic acid probe decreased by 22%. This also confirms accumulation of LPP in the lipoprotein subfraction. It seems likely that an increase in LPP (at least hydroperoxides) in HDL3 after their incubation with oxidized membranes occurs via transport of phospholipids containing LPP from erythrocyte membranes to lipoproteins. The data on the ability of HDL3 to accept LPP from erythrocyte membranes in vitro suggest that HDL3 may have a protective action on cell membranes undergoing oxidation in vivo as well.


Assuntos
Membrana Celular/metabolismo , Eritrócitos/metabolismo , Lipoproteínas HDL/metabolismo , Fosfolipídeos/metabolismo , Naftalenossulfonato de Anilina/farmacologia , Sítios de Ligação , Cátions , Cobre/metabolismo , Corantes Fluorescentes/farmacologia , Humanos , Peróxidos Lipídicos/metabolismo , Modelos Químicos , Ligação Proteica , Transporte Proteico , Espectrometria de Fluorescência , Temperatura , Fatores de Tempo
17.
Biokhimiia ; 46(4): 590-602, 1981 Apr.
Artigo em Russo | MEDLINE | ID: mdl-6793091

RESUMO

The methods for isolation of pure apolipoproteins A-I, A-II and E from the blood plasma of donors for preparation of monospecific rabbit antisera against these apolipoproteins and their estimation in human blood plasma using immunoelectrophoresis are described. It was found that the average content of apolipoprotein A-I (apo A-I) in the blood plasma of healthy males is 126.6 mg%, that of apolipoprotein A-II (apo A-II) is 56.8 mg%, that of apolipoprotein E (apo E) is 10.2 mg%. The apo A-I content in blood plasma is increased in hyper-alpha-lipoproteinemic patients and is decreased in hypo-alpha-lipoproteinemic ones, i. e. there is a direct relationship between the changes in concentration of high density lipoproteins (HDL) and apo A-I. The concentration of apo A-II in dis-alpha-lipoproteinemias varies within a narrow range. A considerable increase of the alpha-cholesterol/apo A-I ratio suggesting an increased capacity of HDL to transport cholesterol in hyper-alpha-lipoproteinemic patients is observed. There exists an indirect correlation between the changes in the contents of apo A-I and apo E in dis-alpha-lipoproteinemic patients.


Assuntos
Apolipoproteínas/sangue , Lipoproteínas HDL/deficiência , Apolipoproteína A-I , Apolipoproteína A-II , Apolipoproteínas/isolamento & purificação , Apolipoproteínas E , Humanos , Imunoeletroforese , Lipoproteínas HDL/sangue
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