The enolases of ice plant and Arabidopsis contain a potential disulphide and are redox sensitive.
The simulated structures of the enolases of Arabidopsis and the common ice plant contain a pair of Cys residues in the correct orientation to form a disulphide bond. Formation of this disulphide might be expected to affect the positioning of several residues in the active site. The enzyme in crude extracts of these two plants is activated by oxidation. Apparently formation of the disulphide crosslink enhances catalysis. The enolases from tomato leaves, maize roots and castor bean embryos lack one of these Cys residues and are not redox sensitive. It seems possible that enolase is redox-regulated by a cytosolic thioredoxin system in a limited number of plant species including ice plant and Arabidopsis.
Anderson
L E
LE
Department of Biological Sciences, University of Illinois at Chicago 60607-7060, USA.
Li
A D
AD
Stevens
F J
FJ
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology*; D001665:Binding Sites; D004220:Disulfides / Q000737:chemistry* / Q000378:metabolism; D004789:Enzyme Activation; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010751:Phosphopyruvate Hydratase / Q000737:chemistry* / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry* / Q000378:metabolism; D010944:Plants / Q000201:enzymology; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid
D004220:Disulfides; D010940:Plant Proteins; D010751:Phosphopyruvate Hydratase