Characteristics of the sucrose uptake system of vacuoles isolated from red beet tissue. Kinetics and specifity of the sucrose uptake system

✍ Scribed by J. Willenbrink; Sabine Doll

• Publisher: Springer-Verlag
• Year: 1979
• Tongue: English
• Weight: 316 KB
• Volume: 147
• Category: Article
• ISSN: 0032-0935
• DOI: 10.1007/bf00389518

✦ Synopsis

The uptake of sucrose against a concentration gradient into the dextran-impermeable [3H]H20 space of red beet (Beta vulgaris L.) vacuoles has been studied using silicone-layer-filtering centrifugation on both fluorometric and l*C-measurement of sucrose. Sucrose transport into vacuoles proceeds partly by an active transport system and partly by passive permeation. The K~(20 ~ C) for active sucrose uptake was found to be about 22 mM and the VM,x(20 ~ C) was about 174 nmol sucrose x (unit betacyanin)-1 x h -1. The temperature dependency of sucrose transport appears to have an activation energy of 35,0 KJ x mol-1. Among various mono-, di-, and trisaccharides tested, raffinose acts as a competitive inhibitor of sucrose uptake.