Oxalate oxidase

Oxalate oxidase catalyzes the reaction shown in Equation (5)  

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For oxalate detection, authors proposed a similar detection approach for recognition of oxalate via an immobilized oxalate oxidase/peroxidase couple and dye precursors MBTH (3-methyl-2-benzothiazolinone hydrazone) and DMAB (3-dimethylaminobenzoic acid). The peroxide generated by oxidation of oxalate to CO2 reacted with the dye precursors in a peroxidase-catalyzed reaction to yield an indamine dye with absorption maximum at 590 nm. The concentration of oxalate was correlated with increased absoiption from dye. 

S. Milardovic, Z. Grabaric, V. Rumenjak, and M. Jukic, Rapid determination of oxalate by an ampero-metric oxalate oxidase-based electrode. Electroanalysis 12, 1051—1058 (2000). 

S. Milardovic, Z. Grabaric, M. Tkalcec, and V. Rumenjak, Determination of oxalate in urine using an amperometric biosensor with oxalate oxidase immobilized on the surface of a chromium hexacyanoferrate-modified graphite electrode. J. AOAC Int. 83,1212—1217 (2000). 

An oxalate sensor by immobilizing spinach tissue as the source of oxalate oxidase was developed by Li [50], The sensor responds linearly to oxalate concentration in the range of 1.0-100 pM with a detection limit of 0.6 pM. The sensor was stable for 30 days when stored at 4°C and a complete analysis for the determination of oxalate could be performed in 1 min including sampling and washing. Considering the low cost of the plant tissue and simple procedure for plant tissue immobilization, this report is most valuable. 

Lahrou NE, Clonis YD. Biomimetic dye-ligand for oxalate requiring enzymes Studies with oxalate oxidase and oxalate decarboxylase. J Biochem 1995 40 59. 

In most terrestrial plant-pathogen interactions a diphenylene-iodonium (DPI)-sensitive (O Donnell et al. 1993), membrane-located, and receptor-activated NADPH oxidase generates superoxide radicals (Levine et al. 1994 Doke and Miura 1995 Lamb and Dixon 1997 Bolwell et al. 1998), which eventually dis-mutate into H202 and 02 (Sutherland 1991). Apoplastic peroxidases (Bolwell et al. 1998 Martinez et al. 1998), as well as various oxidases such as oxalate oxidase (Zhang et al. 1995 Thordal-Christensen et al. 1997) or amine oxidase (Laurenzi et al. 2001 Rea et al. 2002), have also been identified as sources of ROS in higher plants. 

Figure 2-11. Formation of H202 via oxidation of oxalate by oxalate oxidase.

Oxalate Oxalate oxidase Vegetables Possibly related to kidney stones formation... 

Woo, E.J., Dunwell, J.M., Goodenough, P.W., Marvier, A.C., and Pickersgill R.W. 2000. Germin is a manganese containing homohexamer with oxalate oxidase and superoxide dismutase activities. Nat Strut Biol 7 1036-1040. 

Oxalate oxidase. In some instances, as in dry wine, there is not sufficient glucose to effect deoxygenation. However there appears to be sufficient oxalic acid in many wines to act as the substrate for combination with oxygen by oxalate oxidase, derived from the discarded leafy tops of the sugar beet plant (29). The application may still not work well if it relies on catalase to decompose the H2O2 formed by the oxidase, as catalase is strongly inhibited by ethanol at the pH of wine. 

Finally, it must be noted that oxalate oxidation by oxalate oxidase is a different means of degrading oxalate. By this mechanism, oxalate is completely oxidized to CO2 with concomitant production of H2O2. It has no trophic significance and its importance in oxalate cycling is not known. 

Oxalate is determined by using either oxalate decarboxylase (246-248) or oxalate oxidase (242,249) immobilized electrodes. In the former, the CO2 liberated and detected is proportional to the logarithm of the oxalate concentration. Linearity is reported from 0.2 to 10 mM, and the electrodes are stable for more than one month. Human control samples, spiked with oxalate, have been analyzed (246). Oxalate oxidase can be immobilized onto an O2 electrode (242), an amperometric H2O2 sensor (246, 249, 250), and a potentiometric CO2 probe (246) ... 

Why is the operational stability of an enzyme-based thermal sensor for oxalic acid expected to be poorer than an amperometric oxalate sensor prepared using the same enzyme, oxalate oxidase ... 

Laker MF, Hofmann AF, Meeuse BJD. Spectrophoto-metric determination of urinary oxalate with oxalate oxidase prepared from moss. Clin Chem 1980 26 827-30. 

Petrarulo M, CereUi E, Marangella M, Cosseddu D, Vitale C, Linari F. Assay of plasma oxalate with soluble oxalate oxidase. Clin Chem 1994 40 2030-4. 

Assolant-Vinet and Coulet (1986) used a preactivated Biodyne Im-munoaffinity Membrane (Pall, USA) to cover two electrodes working in differential mode. Immobilization was performed by simply dropping the enzyme solution onto the membrane, i.e., the biosensor-users may prepare the enzyme membranes themselves. Good results were obtained with GOD, lactate oxidase, and oxalate oxidase (Coulet, 1987). 

Alternatively, oxalate oxidase (EC 1.2.3.4) can be used, which catalyzes the following reaction ... 

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