Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: KEGG:D02011 (FAD)
 5,530 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Oxalate oxidase (OXO) was purified to homogeneity in three steps from roots of barley seedlings. The purification method comprised: (i) thermal treatment (60 degrees C, 10 min), (ii) affinity chromatography on immobilized either Procion turquoise MX-G dye or biomimetic aminoethyl oxamic blue dye, and (iii) affinity chromatography on immobilized lectin concanavalin A (overall performance: 1096-fold purification, 42% recovery). The purified enzyme has a specific activity of 34 U mg-1 (25 degrees C), and is a homopentamer of M(r) approximately 125,000 (HPLC analysis) showing a single band on SDS-polyacryl-amide gel electrophoresis (M(r) approximately 26,000) after staining with silver nitrate. The kinetic constants of the purified enzyme for oxalate are K(m) 0.27 mM and kcat 22 s-1 (37 degrees C), whereas at [oxalate] > or = 4 mM the enzyme exhibited substrate inhibition. Barley root OXO contains no prosthetic group absorbing at 370 or 450 nm, and riboflavin and FAD have no effect on its activity. The enzyme is activated by 1 mM each of Ca2+ (1.7-fold) and Pb2+ (2.6-fold). Irreversible inactivation studies with denatured (70 degrees C) and native (37 degrees C) enzyme using the sulfhydryl-attacking reagent 5,5-dithiobis(2-nitrobenzoic) acid (1.4 mM), in the presence and absence of SDS, respectively, have shown that denatured OXO (4% SDS, 10 min, 100 degrees C) exhibited 10 HS groups per molecule, whereas native OXO displayed one accessible HS group per molecule after approximately 15 min incubation and, over the same period, maintained its catalytic activity to 90%. Furthermore, native OXO treated with beta-mercaptoethanol (1 mM) lost 83% of its catalytic activity within 5 min. These findings indicate that some cysteines may preserve the catalytic activity of OXO by maintaining the integrity of its tertiary structure via disulfide bond formation.
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PMID:Oxalate oxidase from barley roots: purification to homogeneity and study of some molecular, catalytic, and binding properties. 914 27

In this study, we investigated the development of clinical disease and immune responses in the development of an experimental model of flea allergy dermatitis. Dogs were randomly divided into four treatment groups and were infested with fleas on two different feeding schedules (continuous and episodic). Group 1 consisted of four non-exposed dogs (negative controls) and Group 2 consisted of six dogs exposed to fleas continually. Groups 3 and 4 consisted of 14 dogs each that were exposed to fleas on an episodic schedule (two consecutive days every other week for 12 weeks). Group 4 also received intraperitoneal injections of a low dose of lectin (ricin) with immunomodulatory properties. The purpose of Group 4 was to investigate the effects of ricin on enhancing the development of clinical signs, flea antigen-specific IgE levels and altering the number of CD4+ and CD8+ T cell subsets in peripheral blood. Clinical signs developed in all flea exposed dogs, however, the dermatology lesion scores were less and shorter in duration for continuously exposed dogs compared to episodic exposed dogs, independent of ricin treatment. Lesion development was concentrated in the flea triangle and consisted principally of erythema, followed by alopecia, excoriation, papules, and crusts. CD4+ and CD8+ lymphocyte subsets or IgE levels were not altered by ricin treatment. Flea antigen-specific IgE values were highest in dogs exposed to fleas on a continuous basis compared to those episodically exposed. A greater percentage of clinical responder dogs with negative flea-specific IgE titers or negative intradermal test (IDT) were present in the episodic exposure groups than in the continuous exposure group. IgE titers corresponded slightly better with clinical responders than the IDT. The agreement between the IgE titers and IDT was good (weighted K = 0.67). Histopathology of skin samples were consistent with a Type I hypersensitivity. In conclusion, we were able to develop a model of flea allergy dermatitis by experimentally exposing dogs to fleas on an episodic and continuous feeding schedule. In this study, continuously exposed dogs did not develop immunotolerance, and ricin did not enhance the development of FAD.
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PMID:The immunopathogenesis of flea allergy dermatitis in dogs, an experimental study. 1513 84

Fish skin mucus contains a variety of antimicrobial proteins and peptides that seem to play a role in self defense. We previously reported an antibacterial protein in the skin secretion of the rockfish, Sebastes schlegeli, which showed selective antibacterial activity against Gram-negative bacteria. This study aimed to isolate and structurally and functionally characterize this protein. The antibacterial protein, termed SSAP (S. schlegeli antibacterial protein), was purified to homogeneity by lectin affinity column chromatography, anion-exchange HPLC and hydroxyapatite HPLC. It was found to be a glycoprotein containing N-linked glycochains and FAD. Its molecular mass was estimated to be 120 kDa by gel filtration HPLC and 53 kDa by SDS/PAGE, suggesting that it is a homodimer. On the basis of the partial amino-acid sequence determined, a full-length cDNA of 2037 bp including an ORF of 1662 bp that encodes 554 amino-acid residues was cloned by 3' RACE, 5' RACE and RT-PCR. A blast search showed that a mature protein (496 residues) is homologous to l-amino acid oxidase (LAO) family proteins. SSAP was determined to have LAO activity by the H(2)O(2)-generation assay and substrate specificity for only l-Lys with a K(m) of 0.19 mm. It showed potent antibacterial activity against fish pathogens such as Aeromonas hydrophila, Aeromonas salmonicida and Photobacterium damselae ssp. piscicida. The antibacterial activity was completely lost on the addition of catalase, confirming that H(2)O(2) is responsible for the growth inhibition. This study identifies SSAP as a new member of the LAO family and reveals LAO involvement in the innate immunity of fish skin.
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PMID:Identification of an antibacterial protein as L-amino acid oxidase in the skin mucus of rockfish Sebastes schlegeli. 1714 Apr 17

Amorphous cellulose was used as a specific carrier for the deposition of self-assembled multienzyme complexes capable of catalyzing coupled reactions. Naturally glycosylated fungal cellobiohydrolases (CBHs) of glycosyl hydrolase families 6 and 7 were specifically deposited onto the cellulose surface through their family I cellulose-binding modules (CBM). Naturally glycosylated fungal laccase was then deposited onto the preformed glycoprotein layer pretreated by ConA, through the interaction of mannosyl moieties of fungal glycoproteins with the multivalent lectin. The formation of a cellulase-ConA-laccase composite was proven by direct and indirect determination of activity of immobilized laccase. In the absence of cellulases and ConA, no laccase deposition onto the cellulose surface was observed. Finally, basidiomycetous cellobiose dehydrogenase (CDH) was deposited onto the cellulose surface through the specific interaction of its FAD domain with cellulose. The obtained paste was applied onto the surface of a Clark-type oxygen electrode and covered with a dialysis membrane. In the presence of traces of catechol or dopamine as mediators, the obtained immobilized multienzyme composite was capable of the coupled oxidation of cellulose by dissolved oxygen, thus providing the basis for a sensitive assay of the mediator. Swollen amorphous cellulose plays three different roles in the obtained biosensor as: (i) a gelforming matrix that captures the analyte and its oxidized intermediate, (ii) a specific carrier for protein self-assembly, and (iii) a source of excess substrate for a pseudo-reagent-less assay with signal amplification. The detection limit of such a tri-enzyme biosensor is 50-100 nM dopamine.
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PMID:Application of cellulose-based self-assembled tri-enzyme system in a pseudo-reagent-less biosensor for biogenic catecholamine detection. 1737 47