Uptake of D-glucose and L-proline by oligotrophic and heterotrophic marine bacteria

The transport systems of the oligotrophic bacterium 486 for D-glucose and L-proline have been compared with those of the heterotrophic bacterium RP-303. Kinetic studies demonstrated that the rates of D-glucose and L-proline uptake by the two organisms were saturable processes. The apparent Km values of strain 486 for D-glucose and L-proline were 13.0 microM and 0.2 microM, respectively, whereas those of strain RP-303 were 3.2 microM for D-glucose and 1.8 microM for L-proline. Competition studies indicated that the D-glucose transport system of each bacterium was highly specific for D-glucose. The L-proline transport system of the oligotrophic bacterium 486 had a broad specificity, whereas that of the heterotrophic bacterium RP-303 had a narrow one.