L-Glutamate Oxidase

L-Glutamate oxidase is a potentially very useful tool enzyme, and its coenzyme is flavin adenine dinucleotide, which is a flavin protease. Using L-glutamic acid as a substrate, it is degraded into hydrogen peroxide, ammonia, and α-ketoglutarate, with high substrate specificity. L-glutamate oxidase (GLOD) is an L-amino acid oxidase that uses flavin adenine dinucleotide (FAD) as a coenzyme, without adding exogenous Under the condition of cofactors, L-glutamic acid is deaminated to produce α-ketoglutaric acid, ammonia and hydrogen peroxide. L-Glutamate Oxidase has high specificity and high affinity for the reaction substrate, mild reaction conditions, high catalytic efficiency, and is widely used in food, industrial fermentation and pharmaceutical industries. Since its discovery in the 1980s, this enzyme has been a research hotspot at home and abroad, and is one of the potential tool enzymes. Up to now, the research hotspots of L-Glutamate Oxidase at home and abroad have mainly focused on two aspects. One is to study the mechanism and structure of enzymes with the help of current observation and measurement methods. The other is to continue to develop high-enzyme-producing active strains and how to study them. Use enzyme characteristics to serve human life and industrial applications.

Figure 1. Protein structure of L-Glutamate Oxidase.

Sources of L-glutamic acid oxidase

L-amino acid oxidase is rich in sources, and can be isolated in snake venom, many animals and microorganisms. Microorganisms have a wide range of sources, but their enzyme production capacity is not high. At the current research stage, L-glutamic acid oxidase is mostly isolated from microorganisms. Among them, the ability of Streptomyces to produce enzymes is stronger than other strains, and its enzyme output reaches 6.4 U/ml. The first discovery of L-glutamic acid oxidase was discovered by JURTSHUK and MEMANUS in the membrane preparation of A. veneziarum, but it does not have substrate specificity; the first confirmation in the true sense was KAMEI in 1983 T et al. Confirmed the presence of L-glutamic acid oxidase in the fermentation broth of Streptomycesviolascens. Its relative molecular mass is about 60 000. It has an absorption spectrum characteristic of flavin protein and does not require exogenous auxiliary factors Participation, but its specificity is not strong, and it has an effect on L-glutamic acid, L-glutamine and L-histidine.

Application in the determination of creatinine

In 1993, RUI C S and others used L-glutamic acid oxidase to create a flow injection system to measure the content of blood creatinine. It uses a dual-channel assay to avoid the effects of endogenous glutamate and ammonia in the blood on the assay. The first response is the total response of endogenous ammonia glutamic acid and creatinine; the second response is the response of endogenous ammonia and glutamic acid, and their measurement ranges reach 2 mmol/L and 3mmol/L, respectively. The system has good stability and reproducibility, and has a good correlation with the content of creatinine in the test results obtained by chemical methods.

Application in biosensor

L-glutamic acid has a wide range of functions in the fields of medicine, food additives, nutritional supplements, etc., but its per capita daily intake does not exceed 6 g/d, and excessive consumption of L-glutamic acid will cause obvious poisoning Symptoms are manifested in headaches, dizziness and excessive sweating on the face. Therefore, the detection of L-glutamic acid content in food and clinical samples is very important and necessary. The traditional detection methods commonly used for L-glutamic acid include potentiometric titration, Warburg's respirometry, and chromatographic analysis. These methods are time-consuming and labor-intensive and require high-end precision equipment. Therefore, considering the application of biosensors to detect L-glutamic acid, biosensors have the advantages of fast, high sensitivity, simple equipment, etc.

Conclusions

L-glutamic acid oxidase is a relatively new practical tool enzyme, and its mechanism of action and protein three-dimensional structure are rarely reported. It is hoped that in the near future, with the advancement of biotechnology and molecular biotechnology, researchers can clarify its mechanism of action and construct engineering bacteria that are more suitable for industrial production, so that it can be more widely used and benefit humanity Production and life.

Reference

1. RUI C S.; et al. A flow-injection biosensor system for the amperometric determination of creatinine: simultane-ous compensation of endogenous interferents. Anal Biochem, 1993 (1): 163-171.