Glycollic oxidase

Hydroxyriboflavin. This compound [86120-61 -8] (26) was isolated as a green coen2yme of the NADH dehydrogenase from Peptostreptococms elsdenii and also from glycolate oxidase of porcine Hver. It is not fluorescent, and its stmcture was estabflshed by synthesis (106). The 5 -monophosphate serves as a cofactor for glycolate oxidase from pig Hver. 

Figure 4.3 In most a/p-barrel structures the eight p strands of the barrel enclose a tightly packed hydrophobic core formed entirely by side chains from the p strands. The core is arranged in three layers, with each layer containing four side chains from alternate p strands. The schematic diagram shows this packing arrangement in the a/p barrel of the enzyme glycolate oxidase, the structure of which was determined by Carl Branden and colleagues in Uppsala, Sweden.

Lindqvist, Y. Refined structure of spinach glycolate oxidase at 2 A resolution. /. Mol. Biol. 209 ... 

Figure 18.3 Protein crystals contain large channels and holes filled with solvent molecules, as shown in this diagram of the molecular packing in crystals of the enzyme glycolate oxidase. The subunits (colored disks) form octamers of molecular weight around 300 kDa, with a hole in the middle of each of about 15 A diameter. Between the molecules there are channels (white) of around 70 A diameter through the crystal. (Courtesy of Ylva Lindqvist, who determined the structure of this enzyme to 2.0 A resolution in the laboratory of Carl Branden, Uppsala.)...

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. 

In a related approach, Adam ef al. used glycolate oxidase with D-lactate dehydrogenase for the deracemization of a wide range of racemic a-hydroxy acids (20) (Figure 5.13) [23]. 

Adam, W., Lazarus, M., Boss, B. et al. (1997) Enzymic resolution of chiral 2-hydroxy carboxylic acids by enantioselective oxidation with molecular oxygen catalyzed by the glycolate oxidase from spinach (Spinacia oleracea). The Journal of Organic Chemistry, 62 (22), 7841-7843. 

Adam, W., Lazarus, M., Saha-Moller, C.R. and Schreier, P. (1998) Quantitative transformation of racemic 2-hydroxy acids into (R)-2-hydroxy acids by enantioselective oxidation with glycolate oxidase and subsequent reduction of 2-keto acids with D-lactate dehydrogenase. Tetrahedron Asymmetry, 9 (2), 351-355. 

It should be pointed out that the addition of substances, which could improve the biocompatibility of sol-gel processing and the functional characteristics of the silica matrix, is practiced rather widely. Polyethylene glycol) is one of such additives [110— 113]. Enzyme stabilization was favored by formation of polyelectrolyte complexes with polymers. For example, an increase in the lactate oxidase and glycolate oxidase activity and lifetime took place when they were combined with poly(N-vinylimida-zole) and poly(ethyleneimine), respectively, prior to their immobilization [87,114]. To improve the functional efficiency of entrapped horseradish peroxidase, a graft copolymer of polyvinylimidazole and polyvinylpyridine was added [115,116]. As shown in Refs. [117,118], the denaturation of calcium-binding proteins, cod III parvalbumin and oncomodulin, in the course of sol-gel processing could be decreased by complexation with calcium cations. 

These examples demonstrate that additives can have a beneficial effect on the entrapped biopolymers. Unfortunately, they are generally not universal. The additives need to be found for individual immobilized biopolymers and that is not so easy to do. For instance, lactate oxidase retained its activity in a silica matrix if the enzyme was taken as a complex with poly(N-vinylimidazole) prior to the immobilization, but the polymer did not stabilize glycolate oxidase [87,114], Its stabilization was observed after an exchange of poly(N-vinylimidazole) for poly(ethyleneimine). This is a decisive disadvantage of the approaches because they do not offer a general solution that might be extended to any immobilized biopolymer. 

This enzyme [EC 1.1.3.15] (also referred to as glycolate oxidase, hydroxy-acid oxidase A, and hydroxy-acid oxidase B) catalyzes the reaction of an (5)-2-hydroxy acid with dioxygen to produce a 2-oxo acid and hydrogen peroxide. FMN is the cofactor for this enzyme. This oxidase exists as two major isoenzymes. The A form preferentially oxidizes short-chain aliphatic hydroxy acids whereas the B form preferentially oxidizes long-chain and aromatic hydroxy acids. 

CYTOCHROME P-450 REDUCTASE DIHYDROOROTATE OXIDASE FMN ADENYLYLTRANSFERASE GLUTAMATE SYNTHASE GLYCOLATE OXIDASE (S)-2-HYDROXY-ACID OXIDASE l-LACTATE DEHYDROGENASE (CYTOCHROME)... 

In contrast to the flavin oxidases, flavin dehydrogenases pass electrons to carriers within electron transport chains and the flavin does not react with 02. Examples include a bacterial trimethylamine dehydrogenase (Fig. 15-9) which contains an iron-sulfur duster that serves as the immediate electron acceptor167 169 and yeast flavocytochrome b2, a lactate dehydrogenase that passes electrons to a built-in heme group which can then pass the electrons to an external acceptor, another heme in cytochrome c.170-173 Like glycolate oxidase, these enzymes bind their flavin coenzyme at the ends of 8-stranded a(i barrels similar... 

A barrels nearly circular small helix between /7-strand 8 and a-helix 8 domain covering N-terminus of the barrel glycolate oxidase, trimethylamine dehydrogenase... 

As all enzymes of the mandelate path are located on one operon, the other four enzymes could also be identified, cloned, and sequenced. (S)-Mandelate dehydrogenase [(S)-ManDH] features similarities to glycolate oxidase and flavocyto-chrome b2 (a lactate-DH) both are a/f-barrel proteins and require FMN as cofactor as does (S)-ManDH. It is reasonable to conclude that in this case nature has also sequestered a template that already catalyzes a chemistry similar to the desired reaction. 

If the strand order were 1 2 3 4 5 6, all five connections would be on the same side of the sheet, and no crevice would be formed. However, when eight strands are aligned in this way, a closed barrel of twisted strands can be formed in which strand number 8 is adjacent to strand number 1 (Fig. 34) [72], The helical connections lie outside the barrel, and diverge from the barrel axis, giving geometrical conditions favourable for the formation of crevices at the carboxyl end of the barrel [72], This arrangement occurs in triose-phosphate isomerase [161], pyruvate kinase [162] and glycollate oxidase [163]. 

Lindqvist, Y., Br%ondEn, C-L, Mathews, E. S., and Lederer, E., 1991, Spinach glycolate oxidase and yeast flavocytochrome foj sre structurally homologous and evolutionarily related enzymes wioth distinctly different function and EMN binding, J. Biol. Chem. 266 3198n3207. 

Macheroux, P., Kieweg, V., Massey, V., S derland, E., Stenberg, K., and Lindqvist, Y., 1993, Role of tyrosine 129 in the active site of spinach glycolate oxidase. Fur. J. Biochem. 213 1047nl054. 

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