1983 年 103 巻 10 号 p. 1007-1014
Cation-nutrient cotransport is ubiquitous in nature. For cotransport, coupling between H+ and substrate is common in microbial cells, and that between Na+ and substrate is common in animal cells. We have reported that the melibiose transport system of Escherichia coli could utilize Na+ as a coupling cation. This is the first example of Na+-substrate cotransport found in microbial cells. Versatility in the combination between cation and substrate was revealed. This system seems to be a suitable model system for the analysis of cation-substrate cotransport systems. Physiological, biochemical and genetical properties of this system are summarized.