Effects of glycerol on the in vitro stability and regulatory activation/inactivation of pyruvate,orthophosphate dikinase of Zea mays L. |
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Authors: | G Salahas Y Manetas N A Gavalas |
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Institution: | (1) Laboratory of Plant Physiology, Department of Biology, University of Patras, Patras, Greece |
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Abstract: | Glycerol stabilizes the activity of pyruvate, orthophosphate dikinase extracted from darkened or illuminated maize leaves. It serves as a better protectant of activity than dithiothreitol for the active day-form and the glycerol concentration needed for full protection is inversely related to the level of protein. The night-form of the enzyme is also protected by glycerol not only against inactivation, but also against partial reactivation in storage. Glycerol does not prevent the Pi-dependent activation nor the ADP-dependent inactivation of pyruvate, orthophosphate dikinase, but the rates of both processes are substantially decreased. The ability of the inactive night-form for Pi-dependent activation is also sustained by glycerol for at least 2 h at 20°C, apparently through stabilization of the labile regulatory protein.Abbreviations BSA
bovine serum albumin
- G-6-P
glucose-6-phosphate
- MDH
malate dehydrogenase
- PCMB
p-chloromercuribenzoate
- PEP
phosphoenolpyruvate
- PEPCase
phosphoenol-pyruvate carboxylase
- PPDK
pyruvate, orthophosphate dikinase
- PVP
polyvinylpyrrolidone |
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Keywords: | activation/inactivation glycerol pyruvate orthophosphate dikinase Zea mays L |
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