Maltose uptake and its regulation in<i>Bacillus subtilis</i>

Abstract

Extracts prepared from cultures of Bacillus subtilis, grown on maltose as the sole carbon source, lacked maltose phosphotransferase system activity. There was, however, evidence for a maltose phosphorylase activity, and such extracts also possessed both glucokinase and glucose phosphotransferase system activities. Maltose was accumulated by whole cells of B. subtilis by an energy-dependent mechanism. This uptake was sensitive to the effects of uncouplers, suggesting a role for the proton-motive force in maltose transport. Accumulation of maltose was inhibited in the presence of glucose, and there was no accumulation of maltose by a strain carrying the ptsl6 null-mutation. A strain carrying the temperature-sensitive ptsl1 mutation accumulated maltose normally at 37°C but, in contrast to the wild-type, was devoid of maltose transport activity at 47°C. The results indicate a role for the phosphotransferase system in the regulation of maltose transport activity in this organism.