Partial purification and some properties of a cholinesterase from bush bean (Phaseolus vulgaris L.) roots.
A cholinesterase was partially purified from bush bean (Phaseolus vulgaris L.) roots by using acridinium-based ligand affinity chromatography. The procedure gave a 78-fold increase in specific activity, although at least three inactive contaminants remained. The enzyme activity was maximal against acetyl esters of choline and was inhibited by neostigmine. Di-isopropyl phosphorofluoridate completely inhibited activity at concentrations greater than 0.1 mM. The catalytic centre activity was 2 X 10(-4) times that of electric eel acetylcholinesterase. Cholinesterase activity appeared as a peak (s = 4.2 +/- 0.1 S) after isokinetic sedimentation. The Stokes radius was 4.00 nm and the apparent molecular weight was 72700 +/- 1900. The smallest active and native form of the enzyme appeared to be a monomer. This contrasts with animal acetylcholinesterases, in which the smallest active and native forms are multimeric.
D001665:Binding Sites; D002499:Centrifugation, Density Gradient; D002802:Cholinesterases / Q000302:isolation & purification / Q000378:metabolism*; D002847:Chromatography, Agarose; D004591:Electrophoresis, Polyacrylamide Gel; D007887:Fabaceae / Q000201:enzymology; D007700:Kinetics; D008970:Molecular Weight; D010944:Plants / Q000201:enzymology*; D010946:Plants, Medicinal; D013379:Substrate Specificity
D002802:Cholinesterases