Amino-acid oxidases

Two groups recently achieved in silico identification for ACL racemases by identifying Lys241 as a key amino acid residue [27, 28]. ACL and amino acid amide-racemizing activities were detected among tens of candidates [27]. These newly discovered ACL racemases may be useful for chiral amino acid synthesis by dynamic kinetic resolution and for determining the xmknown physiological functions of ACL racemases. 

Dynamic kinetic resolution of amine by combination of lipase and Pd nanocatalysis Pd nanocatalyst 

However, -stereoselective AOx applicable to the deracemization method have not yet been identified. 

We described the development of a valuable l -stereoselective amine oxidase for the synthesis of (S)-amine through a deracemization reaction [38]. 

Porcine kidney D-amino acid oxidase (pkDAAOx) was identified as the first mammalian flavoprotein to catalyze the oxidative deamination of a-amino acids with strict i -stereoselectivity. pkDAAOx is widely used as a general reagent in research and bioassays of D-amino acids. Although many studies have been conducted on its purification, characterization, gene cloning, expression, and X-ray crystal structure, pkDAAOx was not shown to catalyze the oxidation of amines or even LAAOx, which belongs to the AOx protein family. 

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L-phenylalanine L-amino acid oxidase and horseradish peroxidase (E) I-... 

In another procedure, D-amino acid oxidase (52) is usehil to produce L-amino acids from DL-amino acids. a-Ketocarboxylic acids which are formed by the action of enzymes on D-amino acids, are aminated to form L-amino acids by coupling through the action of amino acid aminotransferases (53). 

L-methionine DL-methionine + Asp D-amino acid oxidase + transaminase Trigonopsis variabilis ... 

D-amino acid oxidase D-amino acids a-keto acids +NH3 2FAD U2 H2U2... 

Riboflavin-5 -Adenosine Diphosphate. Riboflavin-5 -adenosine diphosphate [146-14-5] (flavin—adenine dinucleotide, FAD), C27H33N9O15P2 (2), mol wt 785.56, was first isolated in 1938 from the D-amino acid oxidase as its prosthetic group (95), where it was postulated to be... 

D-Amino acid oxidase will oxidase only serine having the R configuration at C-2. Glycolate oxidase will remove only the prv-R hydrogen of glycolic acid Does the product (0=CHC02H) contain tritium Explain your reasoning. 

Riboflavin was first isolated from whey in 1879 by Blyth, and the structure was determined by Kuhn and coworkers in 1933. For the structure determination, this group isolated 30 mg of pure riboflavin from the whites of about 10,000 eggs. The discovery of the actions of riboflavin in biological systems arose from the work of Otto Warburg in Germany and Hugo Theorell in Sweden, both of whom identified yellow substances bound to a yeast enzyme involved in the oxidation of pyridine nucleotides. Theorell showed that riboflavin 5 -phosphate was the source of the yellow color in this old yellow enzyme. By 1938, Warburg had identified FAD, the second common form of riboflavin, as the coenzyme in D-amino acid oxidase, another yellow protein. Riboflavin deficiencies are not at all common. Humans require only about 2 mg per day, and the vitamin is prevalent in many foods. This vitamin... 

L-Leucine L-Amino-acid oxidase RCOCOO, NH4+, h2o2 Tris pH 7 NH/-glass ... 

Figure 5.4 Deracemization of a-amino acids using D-amino acid oxidase in combination with sodium borohydride.

Recently Turner and coworkers have sought to extend the deracemization method beyond a-amino acids to encompass chiral amines. Chiral amines are increasingly important building blocks for pharmaceutical compounds that are either in clinical development or currently licensed for use as drugs (Figure 5.7). At the outset of this work, it was known that type II monoamine oxidases were able to catalyze the oxidation of simple amines to imines in an analogous fashion to amino acid oxidases. However, monoamine oxidases generally possess narrow substrate specificity and moreover have been only documented to catalyze the oxidation of simple, nonchiral... 

Henn, SW Ackers, GK, Molecular Sieve Studies of Interacting Protein Systems. V. Association of Subunits of D-Amino Acid Oxidase Apoenzyme, Biochemistry 8, 3829, 1969. 

Examples of flavoprotein enzymes include L-amino acid oxidase, an FMN-finked enzyme found in kidney with general specificity for the oxidadve deamination of... 

Amino Acid Oxidases Also Remove Nitrogen as Ammonia... 

While their physiologic role is uncertain, L-amino acid oxidases of liver and kidney convert amino acids to an a-imino acid that decomposes to an a-keto acid with release of ammonium ion (Figure 29-6). The reduced flavin is reoxidized by molecular oxygen, forming hy-... 

Figure 29-6. Oxidative deamination catalyzed by L-amino acid oxidase (i-a-amino acidiOj oxidoreduc-tase). The a-imino acid, shown in brackets, is not a stable intermediate.

Alonso J, JL Barredo, B Diez, E Mellado, E Salto, JL Garcia, E Cortes (1998) D-amino-acid oxidase gene from Rhodotorula gracilis (Rhodosporidium toruloides) ATCC 26217. Microbiology (UK) 144 1095-1101. 

Hamase, K., Inoue, T., Morikawa, A., Konno, R., Zaitsu, K. (2001). Determination of free d-proline and D-leucine in the brains of mutant mice lacking D-amino acid oxidase activity. Anal. Biochem. 298, 253-258. 

Peak concentrations in the blood are obtained between 1 and 3 h after administration. Unlike cysteine (its nonmethylated parent compound), penicillamine is somewhat resistant to attack by cysteine desulfhydrase or L-amino acid oxidase. As a result, penicillamine is relatively stable in vivo [7,2],... 

G.G. Guilbault and G.J. Lubrano, Amperometric enzyme electrodes. Amino acid oxidase. Anal. Chim. Acta 69, 183-185 (1974). 

R. Fernandez-Lafuente, V. Rodriguez, and J.M. Guisan, The coimmobilization of D-amino acid oxidase and catalase enables the quantitative transformation of D-amino acids (D-phenylalanine) into alpha-keto acids (phenylpyruvic acid). Enz. Microb. Technol. 23, 28-33 (1998). 

Fortier [6] found that AQ polymer from Eastman was not deleterious for the activity of a variety of enzymes such as L-amino acid oxidase, choline oxidase, galactose oxidase, and GOD. Following mixing of the enzyme with the AQ polymer, the mixture was cast and dried onto the surface of a platinum electrode. The film was then coated with a thin layer of Nafion to avoid dissolution of the AQ polymer film in the aqueous solution when the electrode was used as a biosensor. These easy-to-make amperometric biosensors, which were based on the amperometric detection of H202, showed high catalytic activity. 

Klein and Olsen126 studied the action of kojic acid on the enzymic oxidation of amino acids by the liver and kidney of rats. Low concentrations of kojic acid in vitro inhibited the oxidation of a number of D-amino acids, L-phenylalanine, and a few related compounds. Kojic acid was found to compete with D-amino acid oxidase for the substrate. 

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