Investigation of the Nature of the Endogenous Glucose Transporter(s) in Insect Cells

다국어 초록 (Multilingual Abstract)

Unlike the mammalian glucose transporter GLUT1, little is known about the nature of the endogenous sugar transporter(s) in insect cells. In order to establish the transport characteristics and other properties of the sugar transport proteins of Sf9 cells, a series of kinetic analyses was performed. A saturable transport system for hexose uptake has been revealed in the insect cells.
The apparent affinity of this transport system(s) for 2-deoxy-d-glucose was relatively high, the Km for uptake being ＜0.5 mM. To further investigate the substrate and inhibitor recognition properties of the insect cell transporter, the ability of other sugars or drugs to inhibit 2-deoxy-d-glueose transport was examined by measuring inhibition constants (Ki).
Transport was inhibited by d-mannose, d-glucose, and d-fructose. However, the apparent affinity of the C-4 epimer, d-galactose, for the Spodoptera transporter was relatively low, implying that the hydroxyl group at the C-4 position may play a role in the strong binding of glucose and mannose to the transporter, The results also showed that transport was stereoselective, being inhibited by d-glucose but not by L-glucose. It is therefore concluded that insect cells contain an endogenous glucose transport activity that in several aspects resembles tee human erythrocyte glucose transporter. However, the mammalian and insect transporters were different in same of their kinetic properties, namely, their affinities for fructose and for cytochalasin B.

목차 (Table of Contents)

• Introduction
• Materials and Methods
• Results
• Discussion