Transport of acidic amino acids inCandida albicans

Abstract

In Candida albicans ATCC 10261, two kinetically different amino acid transport systems with a high (S~) and a low ($2) affinity for aspartic acid (asp) and glutamic acid (glu) were identified. The $1 for the two acidic amino acids was characterized by low Kt values while Kt values of Sz were 30 to 40 times higher. Based on competitive studies of both systems, $1 was found to be specific and common to both asp and glu while $2 was relatively less specific. The Sl and $2 systems were also different in their sensitivity to respiratory inhibitors, mercurials and a K ÷ channel blocker. Both systems, however, showed maximum transport rates during the mid-exponential growth phase.

Characterization of glycolytic metabolism and ion transport of Candida albicans

“…() and Gupta et al . (, ). This primary transporter pumps protons outwards and generates an electric plasma membrane potential (PMP) difference that drives K + inside, as in other fungi.…”

“…() and Gupta et al . (, ). In addition, a Na + /H + antiporter has been described in both C. albicans and C. dubliniensis (Krauke and Sychrova, ).…”

Phenotypic consequences of LYS4 gene disruption in Candida albicans

“…Much higher concentrations of α AA, an intermediate of the lysine biosynthesis pathway, were necessary to induce the respective growth response. The most likely explanation for this phenomenon is the relatively slow uptake of α AA by C. albicans cells (Ye et al ., ; Gupta et al ., ). Growth of the lys4 Δ mutant corresponding to 50% of that of SC5314 was observed at 2.5 m m α AA and of lys21 Δ/ lys22 Δ at 1 m m .…”

Erratum

“…Transport of amino acid was assayed in a reaction mixture containing 5% cell suspension (w/v) (13). The cells were preincubated in 100 mM Tris-citrate pH 4.5, containing cycloheximide (200 ~tg/ml) for 10 minutes at 30°C to inhibit the protein synthesis.…”