>Albrecht Roscher wrote:
>>"Higher plants normally have both an ATP dependent and a PPi dependent
>phosphofructokinase... This is important in plants as they
>have to adapt ... depending on day or night...
>>"These relations should be rather fascinating for some MCA work."
Before anyone gets too excited, Sonnewald's group expressed E coli
pyrophosphatase in potato and tobacco, and did get pronounced phenotypic
effects (Jelitto et al, Planta, 188, 238-244, 1992). However, Sonnewald &
Stitt's groups anti-sensed the f-6-P:PPi phosphotransferase in potatoes,
significantly decreasing its expression, and found no major phenotypic or
metabolic effects (Planta, 192, 16-30, 1994).
Junli Liu in Robert Viola's group at the Scottish Crop Research Institute
has been working on the control analysis and dynamics of the two parallel
enzymes between F6p and FBP. I think some of this has been published -
probably in Eur. J. Biochem - but I can't recall the reference. An
interesting aspect of the problem is that whereas PFK is as usual displaced
from equilibrium, the phosphotransferase step is reckoned to be close to
equilibrium.
That said, anyone who can make sense of all this puzzling stuff is on to
something good, but if I knew the answer, I'd have published it myself.
David
=========================================================
David Fell,
School of Biological & Molecular Sciences,
Oxford Brookes University,
Oxford OX3 0BP, Tel. +44 (0)1865 483247
UK FAX +44 (0)1865 484017
daf at bms.brookes.ac.uk
See my book at: http://www.portlandpress.co.uk/books/isbn/185578047X.htm
