Oxidation glutamic acids

Most of the applications so far focus on the production of the chiral amino acid as the end product. Conversion of the chiral amino acid into the prochiral oxoacid as the end product is less common, although, for instance, Odman etal describe the use of GDH to convert L-glutamate into the higher-value 2-oxoglutarate. Similarly, Findrik et al describe in some detail the kinetics of quantitative conversion of L-methionine into 2-oxo-4-methylthiobutyric acid. In view of the relatively unfavorable equilibrium for amino acid oxidation, thermodynamic and kinetic considerations have to be carefully balanced. A high pH favors oxidative deamination, and fortunately also the PheDH has an unusually high pH optimum, above 10. However, this in itself will not secure... 

An excellent review on protein hydrolysis for amino acid composition analysis has been published by Eountoulakis and Lahm [190], Hydrolysis can be performed by either chemical (under either acidic or basic conditions) or enzymatic means. The acidic hydrolysis itself can be carried out in a liquid or a gas-phase mode. The conventional acid hydrolysis uses 6M HCl for 20-24 h at 110°C under vacuum [200], In these conditions, asparagine and glutamine are completely hydrolyzed to aspartic acid and glutamic acid, respectively. Tryptophan is completely destroyed (particularly in the presence of high concentrations of carbohydrate), while cysteine and sometimes methionine are partially oxidized. Tyrosine, serine, and threonine are partially destroyed or hydrolyzed and correction factors have to be applied for precise quantification [190,201],... 

---