Sucrose Transport into Plasma Membrane Vesicles from Tobacco Leaves by H+ Symport or Counter Exchange Does not Display a Linear Component

Sucrose Transport into Plasma Membrane Vesicles from Tobacco Leaves by H+ Symport or Counter... Uptake of [14C]sucrose by plasma membrane vesicles from leaves of tobacco (Nicotiana tabacum L.) was measured after the imposition of an inwardly directed proton gradient (ΔpH = 2) and an electrical gradient (Δψ = −68 mV, inside negative) across the vesicle membrane. The vesicles were isolated from a microsomal fraction by two-phase partitioning using media that contained 330 mM of either sorbitol or sucrose. Sucrose transport into vesicles isolated using the sorbitol-containing media showed the hallmarks of electrogenic H+ -symport, as it was highly dependent on ΔpH, could be increased three- to four-fold by Δψ, and was abolished by carbonylcyanide m-chlorophenylhydrazone (CCCP). Transport of [14C]sucrose into vesicles that were isolated using the sucrose-containing media apparently occurred by counter exchange. Its initial influx also depended on a low external pH, but it was insensitive to CCCP and hardly stimulated by Δψ. Both symport and counter exchange obeyed simple Michaelis-Menten kinetics. Transport that depends linearly on the external sucrose concentration could not be detected, indicating that the ‘linear’ component that has been observed in sucrose uptake by leaf tissues does not represent a transport route that is provided by the sucrose symporter. The potential role of H+/sucrose-symporters in phloem unloading is briefly discussed. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Journal of Membrane Biology Springer Journals

Sucrose Transport into Plasma Membrane Vesicles from Tobacco Leaves by H+ Symport or Counter Exchange Does not Display a Linear Component

Loading next page...
 
/lp/springer_journal/sucrose-transport-into-plasma-membrane-vesicles-from-tobacco-leaves-by-zczz5IqasX
Publisher
Springer-Verlag
Copyright
Copyright © 2004 by Springer-Verlag
Subject
Life Sciences; Human Physiology; Biochemistry, general
ISSN
0022-2631
eISSN
1432-1424
D.O.I.
10.1007/s00232-004-0657-z
Publisher site
See Article on Publisher Site

References

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 12 million articles from more than
10,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Unlimited reading

Read as many articles as you need. Full articles with original layout, charts and figures. Read online, from anywhere.

Stay up to date

Keep up with your field with Personalized Recommendations and Follow Journals to get automatic updates.

Organize your research

It’s easy to organize your research with our built-in tools.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

Monthly Plan

  • Read unlimited articles
  • Personalized recommendations
  • No expiration
  • Print 20 pages per month
  • 20% off on PDF purchases
  • Organize your research
  • Get updates on your journals and topic searches

$49/month

Start Free Trial

14-day Free Trial

Best Deal — 39% off

Annual Plan

  • All the features of the Professional Plan, but for 39% off!
  • Billed annually
  • No expiration
  • For the normal price of 10 articles elsewhere, you get one full year of unlimited access to articles.

$588

$360/year

billed annually
Start Free Trial

14-day Free Trial