title: Transport of aromatic amino acids by Brevibacterium linens.
abstract: Whole metabolizing Brevibacterium linens cells were used to study the transport of aromatic amino acids. Kinetic results followed the Michaelis-Menten equation with apparent Km values for phenylalanine, tyrosine, and tryptophan of 24, 3.5, and 1.8 microM. Transport of these amino acids was optimum at pH 7.5 and 25 degrees C for phenylalanine and pH 8.0 and 35 degrees C for tyrosine and tryptophan. Crossed inhibitions were all noncompetitive. The only marked stereospecificity was for the L form of phenylalanine. Transport was almost totally inhibited by carbonyl cyanide-m-chlorophenylhydrazone. Iodoacetate and N-ethylmaleimide were much more inhibitory for tryptophan transport than for transport of the other two aromatic amino acids.
mesh_terms: D019297:2,4-Dinitrophenol; D001693:Biological Transport, Active / Q000187:drug effects; D001951:Brevibacterium / Q000378:metabolism*; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D004140:Dinitrophenols / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D006902:Hydroxymercuribenzoates / Q000494:pharmacology; D007700:Kinetics; D010649:Phenylalanine / Q000378:metabolism*; D013696:Temperature; D014364:Tryptophan / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism*
chemical_list: D004140:Dinitrophenols; D006902:Hydroxymercuribenzoates; C030601:4-hydroxymercuribenzoate; D014443:Tyrosine; D010649:Phenylalanine; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D014364:Tryptophan; D019297:2,4-Dinitrophenol