ISSN:
1432-072X
Keywords:
Denitrification
;
Proline transport
;
Photosynthesis
;
Chemical potential of proline
;
proton motive force
;
Rhodopseudomonas sphaeroides f. sp. denitrificans
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Washed cells of Rhodopseudomonas sphaeroides f. sp. denitrificans, prepared from cultures grown anaerobically in light with NO 3 - as the terminal acceptor, readily incorporated [14C]-proline both in light and in the dark. The proline uptake was coupled to the reduction of either NO 3 - , NO 2 - , N2O or O2. Light stimulated the accumulation of proline in these cells. The addition of NO 3 - to washed cells in light decreased the K m for proline from 40 μM to 5.7 μM. Proline transport was inhibited by antimycin A, 2-n-heptyl-4-hydroxyquinoline-N-oxide both in light and in the dark with nitrate indicating that electron transfer from both denitrification and photosynthesis are involved in this uptake. Inhibition by carbonyl cyanide-m-chlorophenyl hydrazone and 2.4-dinitrophenol indicate that proline transport is energy dependent. The H+/proline stoichiometry increased from 1 to 2.5 when the external pH was increased from 6.0 to 8.0. Under these conditions Δμpro increased but Δp decreased markedly above pH 7.0.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00410954
