| Abstract: | The uptake of amino acids by Nitella flexilis has been investigated. Influx of glycine, alanine, and valine appears to be a diffusive process. Influx ranged from 0.14 to 0.06 and 0.04 pmoles/(cm)(sec), respectively. Aspartic acid uptake is an active transport mechanism. The Vmax is 2.8 pmoles/(cm)(sec); the transport constant (Michaelis constant) Km, 7.8 × 10?3 M. The uptake of arginine is apparently due to 2 transport systems, one with a Vmax and Km of 3.1 pmoles/(cm)(sec) and 3.2 × 10?3M, respectively. The second system has a Vmax of 1.4 pmoles/(cm)(sec) and a Km of 2.1 × 10?4 M. The possibility that the second system is diffusive has been considered. |
