| Comments |
"The number of functionally expressed PPRs in the host
membrane of each cell influences the proton flux that can
be generated. The number of PPRs per cell has been spectroscopically quantified in a few studies only, mostly for
PPRs in their natural hosts (Table 1). In the standard
engineering host E. coli, several PPRs have been heterologously expressed, but no quantification of PPRs per cell has
been reported...Besides the number of PPRs per cell, the proton-pumping
rate per PPR determines the generated proton flux. In a
few studies, proton-pumping rates per PPR are reported
(Table 1). Although the published values of the different PPR types vary substantially, it is unfortunately hard to
compare these proton-pumping rates because different
methods and conditions have been used." See notes beneath table |