Calcium Inhibition of Pyrophosphatase in Crude Plant Extracts: IMPLICATION OF SOLUBLE CALCIUM IN C(4) PHOTOSYNTHESIS.
Assays of alkaline pyrophosphatase activity in crude plant extracts are inhibited by soluble calcium coextracted with the enzyme from leaf tissues. Calcium concentrations in most extracts are high enough to interfere seriously with the assay.All C(4) plants examined kept their soluble calcium and interference with pyrophosphatase activity at very low levels, whereas the C(3) plants covered the whole range of soluble calcium concentration. The hypothesis is advanced that low soluble calcium might be a prerequisite for high activity of pyrophosphatase and the C(4) pathway.
Gavalas
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Laboratory of Plant Physiology, University of Patras, Patras, Greece.
Manetas
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Y