Glutamate uptake in Thiobacillus novellus.

Properties of the glutamate uptake system of Thiobacillus novellus were investigated using intact cells. Two kinetically distiguishable components were found and designated at the high-affinity (HA) component with an apparent Km of 33 micronM, and the low-affinity (LA) component with a Km of 18 mM. Glutamate accumulation was temperature-sensitive and could be inhibited by the addition of wide range of inhibitors including cyanide, dinitrophenol (DNP), iodoacetate, mercuric chloride, sodium azide, carbonyl cyanide m-chlorophenyl hydrazone (CCCP), and dicyclhexylcarbodiimide (DCCD). The complex kinetics of the uptake process may be due to the rapid incorporation of added glutamate into a small peptide. This soluble peptide was formed rapidly after glutamate addition, and accumulated in whole cells.