par Gits, Jacqueline ;Grenson, Marcelle
Référence Biochimica et biophysica acta. Biomembranes, 135, 3, page (507-516)
Publication Publié, 1967-07
Article révisé par les pairs
Résumé : 1. 1.The initial rate of entry of l-[14C]methionine into yeast cells appears, on a Lineweaver-Burk plot, to be dependent on two functions. Evidence is presented showing that methionine enters the cell by at least two distinct systems. 2. 2.Mutants which have lost the activity of the methionine permease with a high affinity for methionine (Km = 12 μM and retained the methionine permease with low affinity (Km = 0.77 mM) were isolated and found to be resistant to low doses of l-ethionine. 3. 3.Studies on amino acid uptake in these mutants (met-p1), as well as competition experiments with the wild-type strain, show that the permease with high affinity for methionine is highly specific. 4. 4.Genetic analysis of the met-p1 mutation shows that it is recessive, presents a gene-dose effect, and segregates normally as a single gene which is linked neither to argp-p1 nor to lys-p1. 5. 5.The residual methionine uptake into a met-p1 mutant is inhibited by a few structurally similar amino acids only and seems, on this basis, also to be endowed with a narrow specificity. © 1967.