Premium
The Glucose Transport System in Leishmania tropica Promastigotes *
Author(s) -
SCHAEFER FRANK W.,
MARTIN ELMER,
MUKKADA ANTONY J.
Publication year - 1974
Publication title -
the journal of protozoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 0022-3921
DOI - 10.1111/j.1550-7408.1974.tb03708.x
Subject(s) - extracellular , glucose transporter , intracellular , chemistry , glucose uptake , biochemistry , d glucose , biology , endocrinology , insulin
SYNOPSIS Transport of glucose by Leishmania tropica promastigotes was measured by the uptake of the nonutilizable glucose analog, 2‐deoxy‐D‐glucose (2‐DOG), using the rapid filtration method. Both D‐glucose and 2‐DOG show identical rates of initial uptake. Intracellular 2‐DOG readily exchanges with extracellular D‐glucose and 2‐DOG uptake is competitively inhibited by D‐glucose. These observations suggest that both sugars are taken up by the same system. Neither the glucose analog α‐methyl‐D‐glucoside (α‐MG) nor 3‐0‐methyl glucose (3‐0‐MG) is taken up to any appreciable extent. Transport of 2‐DOG shows saturation kinetics with a V max of 3.2 nmoles/mg cells/min and a K m of 0.16 mM. There is thus a stereospecific, carrier‐mediated transport system for glucose uptake in L. tropica. About 2/3 of the intracellular pool following transport consists of 2‐deoxy‐D‐glucose phosphate (2‐DOG‐P) and the remainder is free, unaltered 2‐DOG.