This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Web of Science (59) Citing Articles via Google Scholar Google Scholar Articles by Shirahashi, K. Articles by Sugiyama, T. Search for Related Content PubMed PubMed Citation Articles by Shirahashi, K. Articles by Sugiyama, T. Agricola Articles by Shirahashi, K. Articles by Sugiyama, T.

Articles

Cold Lability of Pyruvate, Orthophosphate Dikinase in the Maize Leaf ¹

Department of Agricultural Chemistry, School of Agriculture, Shizuoka University, 836 Ohya, Shizuoka 422, Japan

Cold lability of pyruvate, orthophosphate dikinase was investigated using a homogeneous, purified enzyme preparation from maize (Zea mays L. var. Golden Cross Bantam T51) leaves. Its stability was markedly reduced below about 10 C and the rate of cold inactivation followed first order kinetics at a concentration lower than about 0.1 milligram of enzyme per milliliter. Cold inactivation was little affected by pH in the range which gives good stability for the enzyme at warm temperatures and the enzyme activity was protected strongly by inclusion of substrates (pyruvate and phosphoenolpyruvate) and polyols such as sucrose, sorbitol, and glycerol. Loss of catalytic activity was accompanied by an apparent dissociation of a tetrameric form of the enzyme (9S form) into a new, more slowly sedimenting (5.1S) component. Inclusion of pyruvate at 4 mM in the cold-treated enzyme had no effect on the sedimentation value. A sharp change in activation energy of the dikinase-catalyzed reaction was observed near 12 C and its break point appears to be close to the generally accepted critical low temperature limit for the growth of maize plants.

³ To whom requests for reprints should be addressed.

¹ Supported by Grant 256056 from the Ministry of Education of Japan.

This article has been cited by other articles:

				D. Wang, A. R. Portis Jr., S. P. Moose, and S. P. Long Cool C4 Photosynthesis: Pyruvate Pi Dikinase Expression and Activity Corresponds to the Exceptional Cold Tolerance of Carbon Assimilation in Miscanthus x giganteus Plant Physiology, September 1, 2008; 148(1): 557 - 567. [Abstract] [Full Text] [PDF]

				S. L. Naidu, S. P. Moose, A. K. AL-Shoaibi, C. A. Raines, and S. P. Long Cold Tolerance of C4 photosynthesis in Miscanthus x giganteus: Adaptation in Amounts and Sequence of C4 Photosynthetic Enzymes Plant Physiology, July 1, 2003; 132(3): 1688 - 1697. [Abstract] [Full Text] [PDF]