Chloroplast suspensions from spinach (Spinacia oleracea L.) were clearly resolved into intact and stripped chloroplasts by isopycnic centrifugation in density gradients of silica sol ("Ludox") and polyethlene glycol. The intact chloroplasts fixed CO(2) and evolved O(2) more rapidly than the crude suspensions; the stripped chloroplasts were inactive. During the photosynthetic fixation of (14)CO(...

Eight 1-[(2-chlorophenyl)carbamoyl]naphthalen-2-yl alkylcarbamates and eight 1-[(2-nitrophenyl)carbamoyl]naphthalen-2-yl alkylcarbamates were tested for their activity related to the inhibition of photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts. The PET-inhibiting activity of the compounds was relatively low; the corresponding IC50 values ranged from 0.05 ...

The localization of carbamoylphosphate synthetase (CPSase) and aspartate carbamoyltransferase (ACTase), the first two enzymes of the pyrimidine biosynthetic pathway, in chloroplasts was investigated. In dark-grown radish (Raphanus sativus) seedlings, light induced a prominent increase in CPSase activity, but had little effect on ACTase activity. Both enzymes were found in chloroplasts isolated ...

In this study, a series of fourteen ring-substituted 8-hydroxyquinoline derivatives were prepared. The synthesis procedures are presented. The compounds were analyzed using RP-HPLC to determine lipophilicity. They were tested for their activity related to inhibition of photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts. Primary in vitro screening of the synth...

Yeast cationic ferricytochrome c was able to bind to the spinach (Spinacia oleracea) chloroplast envelope with a low affinity (Kd = 1.1 mum). The total amount of low affinity binding sites was of the order of 50 nmol cytochrome c mg(-1) protein. We gave the evidence that binding of ferricytochrome c to the envelope was electrostatic and that the envelope membranes were strongly negatively charg...

Comparison of several lipid reconstitution methods showed that they were not equally efficient at transferring the predominant thylakoid lipid, monogalactosyldiglyceride (MG), to the aqueous phase. We report a reverse phase evaporation method that employs Freon 11 as a lipid solvent and is capable of successfully hydrating MG in spinach (Spinacia oleracea L.) at room temperature within minutes....

Incubation of intact spinach (Spinacia oleracea L.) chloroplasts in the presence of (35)SO(4) (2-) resulted in the light-dependent formation of a chloroform-soluble sulfur-containing compound distinct from sulfolipid. We have identified this compound as the most stable form (S(8)) of elemental sulfur (S(0), valence state for S = O) by mass spectrometry. It is possible that elemental sulfur (S(0...

Cyanide inhibited unesterified fatty acid synthesis but stimulated glyceride synthesis from [1-(14)C]acetate when Spinacia oleracea chloroplasts were incubated in basal media. Both unesterified fatty acid and glyceride accumulation were inhibited when chloroplasts were incubated in a diacylglycerol mode. Stimulation of chloroplast fatty acid synthesis by either exogenous coenzyme A or Triton X-...

Acetate concentration in spinach (Spinacia oleracea L.) leaf tissue has been determined by direct measurement in a leaf extract to oe 70 |xm or less. Additional evidence for such low acetate levels came from isotope dilution experiments where the [ l 14C]acetate incorporation into fatty acids was assayed using purified chloroplasts in the presence o f tissue extracts. Pyruvate dehydrogenase com...