Monooxygenase pyruvate dehydrogenase

NITRATE REDUCTASE NITRITE REDUCTASE PHENOL HYDROXYLASE PROLINE DEHYDROGENASE PUTRESCINE OXIDASE PYRUVATE OXIDASE SALICYLATE 1-MONOOXYGENASE SUCCINATE DEHYDROGENASE SULFITE REDUCTASE XANTHINE OXIDASE Falling ball viscometry,... 

Two enzymes are commonly used for amperometric biosensors, namely lactate oxidase (LOD) and lactate dehydrogenase (LDH). It should be noted that, in this instance, LOD refers to the enzyme which catalyses the reaction shown in Fig. 23.4, in which the products are pyruvate and H202. This type of enzyme was formerly assigned the E.C. number 1.1.3.2, but this was confused with lactate monooxygenase (E.C. 1.13.12.4), which is also commonly referred to as type I lactate oxidase [55] or simply lactate oxidase [56] whose products are acetate, C02 and H202. The LOD which catalyses the reaction shown in Fig. 23.4 has also been referred to as type II lactate oxidase [55] following clarification of this point in a published letter [57], current publications refer to this enzyme as E.C. 1.1.3.x. 

LMO = lactate monooxygenase, LDH = lactate dehydrogenase, PK. = pyruvate kinase, GOD > glucose oxidase, GLOD = glutamate oxidase, (J-gal = (J-galactosidase, GA = glucoamylase... 

Figure 17.6 (a) The principle of an accumulation biosensor, (b) Current-time curves for a sensor operated without and with intermediate accumulation. The difference in the steady state and peak currents represents the amplification of the sensor response, (c) Glycerol measurement without and with NADH accumulation on an enzyme electrode containing immobilized glycerol dehydrogenase, lactate dehydrogenase, and lactate monooxygenase. NADH is stripped by pyruvate addition after 6 min accumulation (reproduced with the permission of Elsevier Science Publishers BV). 

The measurement of the lactate/pyruvate ratio in plasma is possible by using a lactate dehydrogenase-lactate monooxygenase sequence electrode [373]. The sensor is equally sensitive to lactate and pyruvate (Figure 14-34), because of the high enzyme loading and the... 

Figure 14-34. Calibration graph of a lactate dehydrogenase/lactate monooxygenase electrode for ( ) lactate and (X ) pyruvate. (See also Figure 14-36 for sensor conflguration.) Reproduced from [423] with permission from Springer-Verlag.

Schematic representation of a lactate dehydrogenase (LDH) - lactate monooxygenase (LMO) sensor for the determination of pyruvate kinase activity. PEP = phosphoenolpyruvate.

ADP/ATP Hexokinase/pyruvate kinase Oxygen electrode with lactate dehydrogenase/lactate monooxygenase modified carbon-electrode with glucose-6-phosphate dehydrogenase... 

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