Effect of potassium on amino acid transport in yeast

Abstract

Starved yeast cells accumulated potassium when the cation plus glucose was present in the incubation medium. Under these conditions, an increased amino acid transport capacity was developed within 30 to 60 min in comparison with cells incubated only with glucose. There seems to be a correlation between K + accumulation and an increase of the amino acid transport activity. Preincubation in the presence of potassium also produced an increased general protein synthesis. Transport systems are strongly inactivated by ammonium and this effect is partially reverted by potassium preincubation. Results also showed that potassium could ‘protect’ the amino acid transport systems from the inactivation produced by ammonium. It appears that potassium preincubation may have some effect on the rate of synthesis of the amino acid carriers, but effects of potassium appear to exist also on the degradation or inactivation of the carriers.