Using enzymes isolated from diverse sources to determine metal ion cofactors.
Oxidoreductases and hydrolases isolated from different sources (horseradish and peanut peroxidases, alcohol dehydrogenases from baker's yeast and horse liver, and alkaline phosphatases from Escherichia coli, chicken and seal intestine) were used to determine their metal ion cofactors: Fe(III), Zn(II) and Mg(II), respectively. Studying the effects of the metal ion cofactors on the catalytic activity of the enzymes of different origin showed that the extent of their inhibition, activation, or reactivation of their apoenzymes depended on the structure and accessibility of the enzyme active site, which varies among the biocatalysts isolated from different sources. The developed procedures are based on the inhibiting (Zn(II)) or activating (Mg(II)) effects of the metal ions on the catalytic activity of the enzymes, or on reactivating effects (Fe(III) and Zn(II)) on the apoenzymes. The procedures are characterized by high sensitivity and selectivity; the detection limits of Fe(III) using horseradish peroxidase, Zn(II) using alcohol dehydrogenase from baker's yeast, alkaline phosphatase from seal intestine and its apoenzyme, and Mg(II) using alkaline phosphatase from chicken intestine equal 10 ng L(-1), 20 ng L(-1), 3 microg L(-1), 8 microg L(-1) and 0.2 microg L(-1), respectively.
Shekhovtsova
Tatyana N
TN
Chemistry Department, Lomonosov Moscow State University, Leninskie Gory, 119992 Moscow, Russia. shekhov@analyt.chem.msu.ru
Muginova
Svetlana V
SV
D000818:Animals; D003067:Coenzymes / Q000032:analysis* / Q000378:metabolism; D004789:Enzyme Activation; D004798:Enzymes / Q000737:chemistry / Q000378:metabolism*; D008670:Metals / Q000032:analysis* / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism
D003067:Coenzymes; D004798:Enzymes; D008670:Metals; D010940:Plant Proteins