Acta biochimica et biophysica; Academiae Scientiarum Hungaricae最新文献_第2页

Analysis of Ca2+-induced K+-transport of human erythrocytes in propionate media. Ca2+诱导人红细胞在丙酸介质中K+转运的分析。

Acta biochimica et biophysica; Academiae Scientiarum Hungaricae Pub Date : 1985-01-01

B Sarkadi, S Grinstein, A Rothstein, G Gárdos

{"title":"Analysis of Ca2+-induced K+-transport of human erythrocytes in propionate media.","authors":"B Sarkadi, S Grinstein, A Rothstein, G Gárdos","doi":"","DOIUrl":"","url":null,"abstract":"A method is described which allows studying specific cation transport pathways of the cell membranes by converting ion fluxes into volume changes. Lipophilic weak electrolytes, such as propionate, rapidly penetrate the cell membranes in their undissociated acid from but not as negatively charged ions. When human red cells are incubated in isoosmotic K-propionate media an intracellular acidification occurs with a limited propionate uptake and volume increase (corresponding to the buffering capacity of the cytoplasm). If both protons and alkali cations are rendered permeable, a rapid salt influx and volume increase is observed. The latter can be quantitatively followed by electronic sizing methods. A detailed characterization of the system is provided through studies with ionophores, inhibitors of the red cell anion exchange system and drugs which activate or inhibit the Ca2+-induced K+ transport. It is demonstrated that in K-propionate media the permeability of the Ca2+-induced K+ pathway can be directly estimated. The method is suitable to observe population (all-or-none) responses in the activation of the K+ pathway under certain experimental conditions. The application of the method in the search for cation-proton exchanger systems is discussed and its use for demonstration purposes by producing selective lysis of red cells is described.","PeriodicalId":7308,"journal":{"name":"Acta biochimica et biophysica; Academiae Scientiarum Hungaricae","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1985-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13576649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Pyrimidine salvage enzymes in human tonsil lymphocytes: II. Purification and properties of deoxycytidine kinase. 扁桃体淋巴细胞嘧啶挽救酶的研究II。脱氧胞苷激酶的纯化及性质研究。

Acta biochimica et biophysica; Academiae Scientiarum Hungaricae Pub Date : 1985-01-01

K Szyfter, M Sasvári-Székely, T Spasokukotskaja, F Antoni, M Staub

{"title":"Pyrimidine salvage enzymes in human tonsil lymphocytes: II. Purification and properties of deoxycytidine kinase.","authors":"K Szyfter, M Sasvári-Székely, T Spasokukotskaja, F Antoni, M Staub","doi":"","DOIUrl":"","url":null,"abstract":"Human tonsillar lymphocytes incorporate about 7-10 times more [3H]-deoxy-thymidine than [3H]-deoxycytidine at the same extracellular nucleoside concentration, and both incorporations could be inhibited by 10(-5) M arabinosyl-cytosine to 99%. On the other hand, the crude extract of these cells had about 10 times more deoxycytidine kinase than deoxythymidine kinase specific activity, as it was reported previously as well. Therefore, the differences in the labelling of these cells by [3H]-deoxycytidine and [3H]-thymidine cannot be simple due to the different levels of phosphorylating enzymes in the cells. The deoxycytidine kinase of human tonsillar lymphocytes was purified 38.6-fold by DEAE-Sephadex chromatography, and some kinetic and regulatory properties of the purified enzyme were investigated. Deoxycytidine kinase was eluted as a single peak from DEAE-Sephadex column and also from Sephadex G-100 column indicating a molecular weight of about 60 000; no isoenzymes could be detected. During the purification procedure an increase of the enzyme activity was observed suggesting the inhibition of the enzyme in the cells. An apparent Km of 13 microM for deoxycytidine and Ki of 55 microM for arabinosyl-cytosine were found for the tonsillar deoxycytidine kinase. The enzyme was strongly inhibited by dCTP, but not by the other deoxyribonucleoside triphosphates.","PeriodicalId":7308,"journal":{"name":"Acta biochimica et biophysica; Academiae Scientiarum Hungaricae","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1985-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14152052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Liposome mediated DNA-transfer into mammalian cells. 脂质体介导的dna转移到哺乳动物细胞。

Acta biochimica et biophysica; Academiae Scientiarum Hungaricae Pub Date : 1985-01-01

G Somlyai, E Kondorosi, K Karikó, E G Duda

引用次数: 0

Glucocorticoid receptor is activated by heparin and deactivated by plasmin. 糖皮质激素受体被肝素激活，被纤溶酶失活。

Acta biochimica et biophysica; Academiae Scientiarum Hungaricae Pub Date : 1985-01-01

P Arányi, R Machovich

引用次数: 0

Temperature dependence of ATP release from "caged" ATP. 笼中ATP释放的温度依赖性。