Inactivation of Maize Phosphoenolpyruvate Carboxylase by Urea

• Published in: Plant physiology (Bethesda) Vol. 100; no. 3; pp. 1366 - 1368
• Main Authors: Wedding, Randolph T., Paul Dole, Thierry P. Chardot, Wu, Min-Xian
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Physiologists 01.11.1992; Oxford University Press ; American Society of Plant Biologists
• Subjects: Aggregation; Agronomy. Soil science and plant productions; Biological and medical sciences; Corn; Dehydrogenases; Enzymes; Fundamental and applied biological sciences. Psychology; Genetics; Hydrogen bonds; Life Sciences; Ligands; Light scattering; Metabolism; Metabolism and Enzymology; Plant physiology and development; Plants; Plants genetics; Post exposure prophylaxis; Weddings; Monocotyledones; Purification; Zea mays; Enzyme; Plant leaf; Cereal crop; Urea; Regulation(control); Enzymatic activity; Gramineae; Angiospermae; Isolation; Spermatophyta; Inhibition; Phosphoenolpyruvate carboxylase
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.100.3.1366

Phosphoenolpyruvate carboxylase purified from leaves of maize (Zea mays, L.) is sensitive to the presence of urea. Exposure to 2.5 M urea for 30 min completely inactivates the enzyme, whereas for a concentration of 1.5 M urea, about 1 h is required. Malate appears to have no effect on inactivation by urea of phosphoenolpyruvate carboxylase. However, the presence of 20 mM phosphoenolpyruvate or 20 mM glucose-6-phosphate prevents significant inactivation by 1.5 M urea for at least 1 h. The inactivation by urea is reversible by dilution. The inhibition by urea and the protective effects of phosphoenolpyruvate and glucose-6-phosphate are associated with changes in aggregation state.