Uptake of Branched-Chain Amino Acids by Streptococcus thermophilus.
The transport of branched-chain amino acids in Streptococcus thermophilus was energy dependent. The metabolic inhibitors of glycolysis and ATPase enzymes were active, but the proton-conducting uncouplers were not. Transport was optimal at temperatures of between 30 and 45 degrees C and at pH 7.0 for the three amino acids leucine, valine, and isoleucine; a second peak existed at pH 5.0 with valine and isoleucine. By competition and kinetics studies, the branched-chain amino acids were found to share at least a common transport system.
Akpemado
K M
KM
Laboratory of Applied Biochemistry, University of Nancy I, 54506 Vandoeuvre-les-Nancy, Cedex France.
Bracquart
P A
PA