Characteristics of amino acid transport in Saccharomyces cerevisiae cells: Part I--By using respiratory sufficient (rho+) and respiratory deficient (rho) mutants
Verma, R.S.; Prasad, R.
Indian Journal of Biochemistry and Biophysics 20(2): 104-109
1983
ISSN/ISBN: 0301-1208 PMID: 6368370 Document Number: 198873
Transport of L-Glu, L-Lys, L-Leu, L-Arg, L-Ala and Gly was studied in rho+ and rho.degree. cells. All the amino acids accumulated to a varying extent between these 2 cell types. Results with respiratory inhibitors indicated that in rho+ cells, the uptake of Ala, Lys and Leu was mediated by an active process. In rho.degree. cells, however, the uptake of all the amino acids was mediated as these inhibitors did not affect their overall accumulation. The enhanced rate of amino acid uptake at low pH (3.0) in rho.degree. cells were associated with high affinities of the amino acids for the carrier(s) as shown by their decreased apparent Km values. No such distinct stimulation at low pH was observed in rho.degree. cells; also apparent Km values remained unaffected at low external pH.