Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Pterins, fractionation

Some commonly used detectors are UV (at 280 nm), ELD, ED and microbiological assay of collected fractions. UV presents a low sensitivity, but all folate derivatives respond to this detection. ELD is used even if some compounds, like folic acid, do not fluoresce. Therefore, a postcolumn derivatization, involving hypochlorite to cleave folic acid, di- and tetra-hydrofolic acid oxidatively to fluorescence pterins [571], has been introduced. Eewer reports on the use of LC-MS for folate detection are available in the literature [578-580]. [Pg.623]

Figure 9.130 Identification of the products of folic acid C9-N10 cleavage. (A) [2-l4C]folic acid was incubated with FAS and coinjected with pterin-6-aldehyde. Radioactivity was measured in 0.5 niL fractions. (B) [7,9,3, 5 -3H]folic acid was incubated with FAS and coinjected with pterin-6-aldehyde and p-aminobenzoylglutamic acid. Radioactivity was determined in 0.5 mL fractions. Arrows indicate retention volumes of related compounds. Abbreviations P-6-COOH, pterin-6-carboxylic acid 6-HMP, 6-hydroxymethylpterin P-6-CHO, pterin-6-aldehyde FA, folic acid p-ABGA, p-aminobenzoylglutamic acid. (From De Witt et al., 1983.)... Figure 9.130 Identification of the products of folic acid C9-N10 cleavage. (A) [2-l4C]folic acid was incubated with FAS and coinjected with pterin-6-aldehyde. Radioactivity was measured in 0.5 niL fractions. (B) [7,9,3, 5 -3H]folic acid was incubated with FAS and coinjected with pterin-6-aldehyde and p-aminobenzoylglutamic acid. Radioactivity was determined in 0.5 mL fractions. Arrows indicate retention volumes of related compounds. Abbreviations P-6-COOH, pterin-6-carboxylic acid 6-HMP, 6-hydroxymethylpterin P-6-CHO, pterin-6-aldehyde FA, folic acid p-ABGA, p-aminobenzoylglutamic acid. (From De Witt et al., 1983.)...
The inducible arsenite oxidase from the Eubacterium Alcaligenes faecalis (NCIB 8687) has been purified and characterized (22-24). Anderson et al. (24) isolated the enzyme from a sonicate of washed, lysozyme-treated cells that had been harvested in their late exponential growth phase. The sonicate was fractionated by gel filtration through DEAE-sepharose and active fractions concentrated by ultrafiltration. The purified enzyme was found to be monomeric with a molecular mass of 85 kDa. It consisted of two polypeptide chains in an approximate ratio of 70 30. The enzyme stmcture included one molybdenum, five or six iron atoms, and sulfide. Purification of the oxidase also led to recovery of azurin, a blue protein, which was rapidly reduced by arsenite in the presence of catalytic amounts of Aro, and a red protein. The red protein was a c-type cytochrome, which was reduced by arsenite in the presence of catalytic amounts of Aro and azurin. No reduction of the cytochrome occurred in the absence of Aro, but it did occur in the absence of azurin. Denaturation of Aro led to the release of a pterin cofactor characteristic of molybdenum hydroxylases. In intact cells of A. faecalis, the enzyme resides on the outer surface of the inner (plasma) membrane. The cytochrome and azurin may be part of an electron transfer pathway in the periplasm. [Pg.320]

Some of the substances that have been separated by this method are given in papers referred to by Morris and Morris (1964) amino acids, peptides (particularly those having molecular weights ranging from 500 to 5000), polypeptide antibiotics, proteins (including enzymes), carbohydrates (although for most compounds in this chemical class other fractionation methods are much more frequently applied), purines, pyrimidines, nucleic acid derivatives, tRNA s that are specific for various amino acids, organic acids, steroids, lipids, antibiotics that are not peptides, porphyrins, pterins, vitamin B,2 and other vitamins, lipoic acid, and alkaloids. The countercurrent-distribution procedure of Holley et al. (1965) is widely used, sometimes with modifications. Korte et al. (1965) have separated three isomers of tetrahydrocannabinol. [Pg.554]

Mazza and Penati (84,85) have isolated active materials containing, 1 hey believe, a nucleotide, a polypeptide, and a pterine. Their steps of fractionation are summarized in Table XIX. [Pg.279]

From these properties, the conclusion was drawn that the substance is a complex purine, resembling members of the pterine series of Wieland and Schflpf. Later work by SubbaRow indicates that fraction C is composed, for the most part, of xanthine, accompanied by several other difficultly separable substances. ... [Pg.448]


See other pages where Pterins, fractionation is mentioned: [Pg.546]    [Pg.141]    [Pg.91]    [Pg.33]    [Pg.34]    [Pg.35]   
See also in sourсe #XX -- [ Pg.546 , Pg.554 ]




SEARCH



Pterin

Pterins

© 2024 chempedia.info