International Journal of Electrochemistry

Review Article

Design and Development of Biosensors for the Detection of Heavy Metal Toxicity

Table 3

Principle of detection using enzyme-based biosensors.
EnzymeReactionEquationsReferences
(1) (2)(3) (4)
Alkaline phosphatase (EC: 3.1.3.1, ALP)orttophosphoric monoester +H2O A L P − − − → alcohol + H3PO4(16)[12–14, 32]
Urease (EC: 3.5.1.5)NH2CONH2+3 H2O u r e a s e − − − − → 2 NH4+ +HCO3− + OH−(17)[5, 33–38]
Urease/glutamate dehydrogenase (GLDH)NH2CONH2 + H2O u r e a s e − − − − → CO2 + 2 NH3(18)[39]
NH3 + α-ketoglutarate + NADH + H+ G L D H − − − − → L-glutamate + NAD+(19)
Tyrosinase (EC: 1.14.18.1, Ty)343125.tab.003a(20) [40, 41]
343125.tab.003b(21)
Acetylcholinesterase (EC: 3.1.1.7, AChE)2(CH3)3N+(CH2)2SCOCH3+H2O A C h E − − − − → (CH3)3N+(CH2)2SH + CH3COOH(22) [42, 43]
2(CH3)3N+(CH2)2SH - 2e- → 2(CH3)3N+(CH2)2 S - S(CH2)2N+(CH3)3 + 2H+(23)
Nitrate reductase (EC: 1.7.1.2, NR or NAD(P)H-NR)NO3− + NAD(P)H + H+ N R − − → NO2− + NAD(P)+ + H2O(24)[44, 45]
PQQ glucose dehydrogenase (EC: 1.1.5.2, PQQ-GDH)D-glucose + ubiquinone P Q Q − G D H − − − − − − − → D-glucono-1,5-lactone + ubiquinol(25)[15]
Glycerol-(PQQ) 1-oxidoreductase (EC: 1.1.99.22, PQQ-GlyDH)Glycerol+ acceptor (ox) P Q Q − G l y D H − − − − − − − − → glycerine/dihydroxyacetone + acceptor (red)(26)[46]
Glucose oxidase (EC: 1.1.3.4, GOx)first generation glucose + Gox(FAD) + H2O ⇔ [glucose-Gox(FAD)] → gluconic acid + Gox(FADH2)(27) [20, 47]
O2 + Gox(FADH2) ⇔ [O2-Gox(FADH2)] → H2O2 + Gox(FAD)(28)
second generation glucose + Gox(FAD) + H2O ⇔ [glucose-Gox(FAD)] → gluconic acid + Gox(FADH2)(27)
Mox + Gox(FADH2) → Mred + Gox(FAD) + 2H+(29)[48]
Mred → Mox + e−(30)
Invertase (EC: 3.2.1.26, Inv)/GoxSucrose + H2O I n v − − → α-D-glucose + D-fructose(31)[49]
α-D-glucose + O2 G o x − − → D-gluconic acid + H2O2(32)
Invertase/Mutarotase/GoxSucrose + H2O I n v − − → α-D-glucose + D-fructose(33)
α-D-glucose M u t a r o t a s e − − − − − − − → β-D-glucose(34)[50]
β-D-glucose + O2 G o x − − → D-gluconic acid + H2O2(32)
H2O2 P t − → O2 + 2H+ + 2e−(35)
H2O2 + HRPred → H2O + HRPox(36)
Horseradish peroxidase (EC: 1.11.1.7, HRP)343125.tab.003c(37)[7]
343125.tab.003d(38)
L-lactate dehydrogenase (EC: 1.1.1.27, LDH)/L-lactate oxidase (EC: 1.13.12.4, LOD)NADH + H+ + pyruvate L D H − − − → L-lactate + NAD+(39) [22]
L-lactate + O2 L O D − − − → pyruvate + H2O2(40)