Mechanism of purine nucleoside handling and transport in isolated membrane vesicles from polyoma transformed BHK/21 cells

Dowd, Diana J.; Quinlan, Dennis C.; Hochstadt, Joy

doi:10.1021/bi00639a030

Cited by 17 publications

(2 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Mammalian cells are known to possess several forms of nucleoside transport that vary with respect to their kinetic parameters (4,22), sodium dependence (17,27), and sensitivity to NBMPR (3,22). Additionally, rodent (12,24) and human (10) cells have been shown to possess two types of inosine transport system, the first a facilitated diffusion mechanism and the second a purine nucleoside phosphorylase-dependent group translocation. The hypothesis that the complex phenotype of 80-5D2 cells can be attributed to alterations in more than one gene product must be considered.…”

Section: Discussionmentioning

confidence: 99%

Incomplete nucleoside transport deficiency with increased hypoxanthine transport capability in mutant T-lymphoblastoid cells.

Aronow¹,

Hollingsworth²,

Patrick³

et al. 1986

Mol. Cell. Biol.

View full text Add to dashboard Cite

show abstract

Section: Discussionmentioning

confidence: 99%

Incomplete nucleoside transport deficiency with increased hypoxanthine transport capability in mutant T-lymphoblastoid cells.

Aronow¹,

Hollingsworth²,

Patrick³

et al. 1986

Mol. Cell. Biol.

View full text Add to dashboard Cite

show abstract

“…Membrane vesicles from CLE -1 cells CLE-1 cells were subjected to the membrane preparation procedure described earlier (Hochstadt et al, 1975;. The results of marker enzyme assays indicated that the fractionation procedure yielded a higher purification of the plasma membrane markers than that obtained with several fibroblast cell lines (Hochstadt et al, 1975;Li and Hochstadt, 1976a;Dowd et al, 1977). CLE-1 vesicles had 40-fold more 5'-AMPase specific activity (a plasma membrane marker) than the cell homogenate (92.7 pmol/min.kg vs 2.3 pmol/min.pg), while mitochondria1 contamination, as judged by succinic dehydrogenase specific activity, was less than 5% (45 pmole/ min.pg in the homogenate 2.3 pmol/min.pg in the vesicles).…”

Section: Uptake Of Aib and Leucine By Cle-1 Cellsmentioning

confidence: 99%

Nutrient transport in a bovine lens epithelial cell line

Prasad

Shopsis

Southern

et al. 1981

Journal Cellular Physiology

Self Cite

View full text Add to dashboard Cite

A bovine calf lens epithelial cell line (CLE-1) that synthesizes crystallin has been established in culture and some of its transport properties have been characterized using both cells and membrane vesicles derived from them. The membrane vesicles fractionate with high recovery of plasma membrane markers, showing a 40-fold purification of 5'-AMPase and a 20-fold decrease in the specific activity of the mitochondrial marker enzyme succinic dehydrogenase relative to a cell homogenate. Transport sites demonstrated higher specific activity than has been seen in vesicles from cell lines studied previously. The uptake of alpha-amino isobutyric acid (AIB) (an alanine analog) by CLE-1 cells is stimulated four- to fivefold by Na+ and exhibits a Km of 5.4 mM with a Vmax of 50 pmoles/min.microgram of cell protein. The uptake of leucine was not Na+ stimulatable. The uptake of AIB by the cells was reduced by 43% at confluence. Thus, the cell density dependent behavior of the uptake of the alanine amino acid family in CLE-1 is similar to that of various fibroblast cells. The Na+ caused a threefold stimulation of AIB uptake in the membrane vesicles, while vesicular uptake of leucine was unaffected by Na+. The uptake of adenine, guanine, uridine, and guanosine was also tested in these vesicles. The substrates were rapidly accumulated, came to a steady state distribution within 1-2 minutes, and were recovered as the unaltered compounds after uptake.

show abstract

Adenosine transport and metabolism in mouse leukemia cells and in canine thymocytes and peripheral blood leukocytes

Lum

März

Plagemann

et al. 1979

Journal Cellular Physiology

View full text Add to dashboard Cite

The intracellular accumulation of free 13H1 adenosine was measured by rapid kinetic techniques in P388 murine leukemia cells in which adenosine metabolism (phosphorylation and deamination) was completely prevented by depletion of cellular ATP and by treatment with deoxycoformycin. Nonlinear regression of integrated rate equations on the data demonstrate that the time courses of labeled adenosine accumulation at various extracellular adenosine concentrations in zero-trans and equilibrium exchange protocols are well described by a simple, completely symmetrical, transport model with a carrier:substrate affinity constant of about 150 pM. Adenosine transport was not affected by 1 mM deoxycoformycin indicating that this analog has a low affinity for the nucleoside transport system. The transport capacity of dog thymocytes and peripheral leukocytes was similar to that of P388 cells. Transport was not inhibited by deoxycoformycin and remained constant during the first two hours after mitogenic stimulation with concanavalin A. In untreated, metabolizing P388 cells transport was found to be the major determinant of the rate of intracellular metabolism, regardless of the extracellular adenosine concentration (up to a t least 160 pM), but the long-term accumulation (longer than 30-60 seconds) of radioactivity from extracellular adenosine strictly reflected the rate of formation of nucleotides (mainly ATP). The metabolism of adenosine by whole cells was entirely consistent with the kinetic properties of the transport system and those of the metabolic enzymes.At low exogenous adenosine concentrations (1 pM and below) transport was slow enough to allow direct phosphorylation of most of the entering adenosine. The remainder was deaminated and rapidly converted to nucleotides via inosine, hypoxanthine, and IMP. At concentrations of 100 p M or higher, on the other hand, influx exceeded the maximum velocity of adenosine kinase about 100 times so that most of the entering adenosine was deaminated. But since the maximum velocity of adenosine deaminase exceeded those of nucleoside phosphorylase and hypoxanthinelguanine phosphoribosyltransferase about 5 and 100 times, respectively, hypoxanthine and inosine rapidly exited from the cells and accumulated in the medium. A 98% reduction of adenosine transport (at 100 pM), caused by the transport inhibitor Persantin, inhibited adenosine deamination by whole cells to about the same extent as transport, whereas adenosine phosphorylation was relatively little affected; thus in the presence of Persantin, transport and metabolism resembled that occurring at the low adenosine concentration. These and other results indicate that adenosine deamination is an event distinct from transport, which occurs only subsequent to adenosine's transport into the cell.

show abstract

Mechanism of purine nucleoside handling and transport in isolated membrane vesicles from polyoma transformed BHK/21 cells

Cited by 17 publications

References 15 publications

Incomplete nucleoside transport deficiency with increased hypoxanthine transport capability in mutant T-lymphoblastoid cells.

Incomplete nucleoside transport deficiency with increased hypoxanthine transport capability in mutant T-lymphoblastoid cells.

Nutrient transport in a bovine lens epithelial cell line

Adenosine transport and metabolism in mouse leukemia cells and in canine thymocytes and peripheral blood leukocytes

Contact Info

Product

Resources

About