Spinach chloroplasts, inhibition Hill reaction

Table II Inhibition of Hill Reaction in Spinach Chloroplasts...

Aminoacid-tRNA synthetases were isolated from spinach chloroplasts by methods developed at Jealott s Hill. Cytoplasmic aaTRS s from carrot were isolated by standard procedures. Compounds were assayed as inhibitors of the chloroplastic aaTRS s at a single rate, 10 pM. The reaction was followed by phosphate generation and the percentage inhibition determined using literature methods. The IC50 value for the spinach chloroplastic enzymes and inhibition data for carrot cytoplasmic aaTRS s were determined for compounds of interest. All compounds were tested for post-emergence herbicidal activity, at 0.125, or at 0.5, or at 2.0 k a in standard screens." ... 

Binding Events Modeled with Quantum Chemical Descriptors. Inhibition of the Hill reaction (spinach chloroplasts) correlates with the energy level of the highest occupied MO on amide nitrogen for a series of piperldinoacetanilides (139). Electron density on amide nitrogen also correlates well with E,... 

Arnon and his collaborators (11,15) have reported that whole spinach chloroplasts, prepared in 0.5 M glucose or 0.35 M NaCl, are able to carry out not only the Hill reaction (f.c., the photolysis of water in the presence of artificial hydrogen acceptors) but also photosynthetic phosphorylation and carbon dioxide fixation. Both these processes are light-dependent and strongly inhibited by o-phenanthroline, which interferes with the photochemical reaction. Their early results are shown in Table V. These important findings... 

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