Phosphoenolpyruvate Carboxylase from Spinach Leaf Tissue: Inhibition by Sulfite Ion 1
AUTOR(ES)
Mukerji, S. K.
RESUMO
Phosphoenolpyruvate carboxylase (EC 4.1.1.31), partially purified from spinach (Spinacia oleracea) leaves, is inhibited by SO32− ion. The inhibition is competitive or mixed type with respect to HCO3− (Ki = 17 mm), and noncompetitive with respect to phosphoenolpyruvic acid (Ki = 11 mm), Mg2+ (Ki = 10 mm), and Mn2+ (Ki = 2.4 mm). The inhibitory effect of SO32− is more significant in the presence of Mn2+ than in the presence of Mg2+. l-Malate, an inhibitor of phosphoenolpyruvate carboxylase activity, and SO32− may bind at the same site on the enzyme. Glyoxal bisulfite and glyoxylate bisulfite are equally effective inhibitors of the enzyme activity as SO32−, but α-hydroxypyridinemethanesulfonate is a weak inhibitor. The data are discussed in relation to the physiological effect of the air pollutant (SO2) on plant leaf metabolism.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=541457Documentos Relacionados
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