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001-es BibID:	BIBFORM004945
Első szerző:	Heijn, Marc
Cím:	Anthracyclines modulate multidrug resistance protein (MRP) mediated organic anion transport / Marc Heijn, Jan H. Hooijberg, George L. Scheffer, Gábor Szabó, Hans V. Westerhoff, Jan Lankelma
Dátum:	1997
ISSN:	0005-2736
Megjegyzések:	We studied the ATP-dependent uptake of dinitrophenyl-glutathione (GS-DNP) into plasma membrane vesicles derived from parental GLC4 cells and from multidrug resistant GLC4/ADR cells. The latter have a high expression of the multidrug resistance protein (MRP). Uptake of GS-DNP into membrane vesicles from GLC4/ADR cells was highly stimulated by the addition of ATP, compared to the uptake into membrane vesicles from GLC4 cells. This ATP-dependent uptake into membrane vesicles from GLC4/ADR cells was saturable with a Km of 1.2 +/- 0.2 microM and a Vmax of 560 +/- 80 pmol/mg prot./min. ATP stimulated GS-DNP uptake with a Km of 187 +/- 4 microM. This uptake was specifically inhibited by a polyclonal serum raised against a fusion protein containing a segment of MRP. The ATP-dependent uptake of GS-DNP was not only inhibited by organic anions, such as oxidized glutathione (GSSG), methotrexate (MTX) and some bile acids, but also by non-anionic natural product drugs, such as anthracyclines, vinca alkaloids and etoposide (VP-16). Uptake of GSSG and MTX into membrane vesicles from GLC4/ADR cells could be stimulated by ATP. The ATP-dependent uptake of GSSG had a Km of 43 +/- 3 microM and a Vmax of 900 +/- 200 nmol/mg protein/min. The ATP-dependent uptake of GS-DNP seemed to be non-competitively inhibited by the anthracycline daunorubicin (DNR), whereas the ATP-dependent GSSG uptake seemed to be competitively inhibited by DNR. A substrate binding site on MRP is proposed that comprises a pocket in which both DNR and GS-DNP or GSSG bind in random order to different, only partly overlapping sites. In this pocket binding of a second compound is influenced by the compound which was bound first.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban Drug resistance, multiple Biological transport Adenosine triphosphate Kinetics Glutathione/aa Daunorubicin
Megjelenés:	Biochimica et Biophysica Acta (BBA). Biomembranes. - 1326 : 1 (1997), p. 12-22. -
További szerzők:	Hooijberg, Jan H. Scheffer, George L. Szabó Gábor (1953-) (biofizikus) Westerhoff, Hans V. Lankelma, Jan
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001-es BibID:	BIBFORM043988
Első szerző:	Szabó Gábor (biofizikus)
Cím:	Light-induced permeabilization and merocyanine 540 staining of mouse spleen cells / Szabo Gábor, Rédai Imre, Bacso Zsolt, Hevessy Jozsef, Damjanovich Sándor
Dátum:	1989
ISSN:	0005-2736
Megjegyzések:	Merocyanine 540 (M540) is a potential-sensitive, hydrophobic dye that preferentially incorporates into the 'fluid' domains of cellular membranes, distinguishing between hemopoietic cells according to their differentiation state. A bright staining with M540 is usually achieved by UV illumination of the cells during staining. We show by flow cytometric analysis that: (1) staining is greatly enhanced by UV illumination of mouse spleen cells before addition of the dye; (2) UV treatment causes an increased permeability toward propidium iodide and intracellular fluorescein as well; (3) the increment in M540 fluorescence precedes permeabilization to propidium iodide, while the latter precedes leakage of fluorescein. We also describe an overshoot and accelerated recovery of M540 fluorescence after photobleaching by a 514 nm laser beam. It is suggested that penetration of M540 to the more fluid inner membrane structures explains the fluorescence increment in both experiments.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Biochimica et Biophysica Acta (BBA). Biomembranes. - 979 : 3 (1989), p. 365-370. -
További szerzők:	Rédai Imre (1961-) (sebész, aneszteziológus) Bacsó Zsolt (1963-) (biofizikus) Hevessy József Damjanovich Sándor (1936-2017) (biofizikus)
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