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KMID : 1235920110030010038
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Medical Journal of Catholoc University of Daegu
2011 Volume.3 No. 1 p.38 ~ p.43
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Evaluation of Pentose Effects on D-Glucose Transport of the Sugar Transport systems Present in Trichoplusia ni Cells
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Lee Chong-Kee
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Abstract
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Purpose: Very little is known about properties of the endogenous sugar transport system in Trichoplusia ni cells,
although the cells are commonly employed as the host permissive cell line to support the baculovirus AcNPV replication and the human HepG2 type glucose transport protein synthesis. In order to investigate the transport characteristics of the insect cell transport system, the affinities of the insect cell transporter for different pentoses were assessed by examining the ability of these sugars to inhibit 2-deoxy-D-glucose transport in T. ni cells.
Materials and Methods: The pentose transport characteristics of the insect cells were investigated using 2-[1,2-3H]-deoxy-D-glucose (2dGlc) by measuring inhibition constants (Ki). Since the same substrate was used for all experiments of this type, the apparent Ki values for each pentose should provide a measure of their relative affinities.
Results: The uptake of 2dGlc in the T. ni cells followed a simple linear function of time for at least 2 min. The
transport was inhibited by D-xylose and D-ribose, but not L-xylose. D-ribose had a greater apparent affinity for the T. ni transport system than D-xylose. Cytochalasin B binding activity for the insect cell and the cells infected with the recombinant baculovirus at the concentration of 1 mg per ml were 0.001 and 1.327, respectively.
Conclusion: The results obtained have shown the existence of a saturable transport system for pentose uptake by the insect cells. The results also showed that the transport was stereoselective, being inhibited by D-xylose, not by Lxylose. Unlike the human HepG2 type glucose transporter, D-ribose had a somewhat greater apparent affinity for the insect cell transporter than D-xylose. It is therefore concluded that the insect cells appeared to contain an endogenous
sugar transport activity that in several aspects resembles the human counterpart. In addition, cytochalasin B binding activity was absent for the insect cell transport system. Therefore, the presence of endogenous transporters should not
interfere with the assay of the cytochalasin B binding properties of human transporter expressed in insect cells.
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KEYWORD
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Insect cells, Pentose transport, Transport assay
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