Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The synthetic chemical 4-aminobiphenyl (4-ABP) has been shown to be a bladder carcinogen in both man and animals. A valid radioimmunoassay for a metabolite of 4-ABP has been developed as a means to monitor potential human exposure to 4-ABP. The antibody was produced by the immunization of two female New Zealand White rabbits and was found to be highly specific for 4-acetamidobiphenyl (4-AABP), the acetylated metabolite of 4-ABP. At an initial dilution of 1/5000, the antisera bound 45% of the [125I]-labeled derivative of 4-ABP. This derivative was prepared by coupling 4-hemisuccinamidobiphenyl (4-HSBP) with tyramine, and then radioiodinating this compound using the enzymatic lactoperoxidase method. The dose of 4-acetamidobiphenyl which would displace 50% of the labeled hapten initially bound to the antiserum, was about 1 ng (4.8 pmol). Scatchard analysis of the standard curve binding data indicated the presence of at least two populations of binding sites. The equilibrium association constant for the higher binding affinity component was 2.8 x 10(8) Liters/mole. A series of 210 randomly selected human urine control samples were analyzed and a nonspecific background contribution of 1.67 +/- 0.07 ng (mean + S.E.) of "4-acetamidobiphenyl"/mL urine was found.
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PMID:Development of a radioimmunoassay procedure for 4-acetamidobiphenyl, a metabolite of the chemical carcinogen 4-aminobiphenyl, in urine. 742 Nov 40

At mole ratios of lactoperoxidase to tubulin monomers of 3-4, bovine lactoperoxidase forms 1:1 adducts with both alpha- and beta-tubulin from rat brain, thereby separating the tubulin heterodimer into its monomers. This mixture binds colchicine normally, and we show here by direct photoaffinity labeling that the bulk of the [3H]colchicine becomes attached to beta-tubulin under these conditions. When the alpha-tubulin has been displaced by lactoperoxidase, the ratio of label in beta-tubulin to alpha-tubulin is increased. The amount of label in alpha-tubulin decreases with a corresponding appearance of label in lactoperoxidase. The rate of labeling of beta-tubulin remains slow. We conclude that alpha-tubulin is not necessary for colchicine binding and propose a model wherein the A and C rings of colchicine bind to beta-tubulin, while the B ring faces alpha-tubulin in the dimer.
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PMID:Colchicine binding by the "isolated" beta-monomer of tubulin. 762 94

The time course of the peroxidative bromination of propylene accompanied by in situ generation of hydrogen peroxide by glucose oxidase was examined to improve the productivity of propylene bromohydrin. To prevent the rapid inactivation of lactoperoxidase by excess hydrogen peroxide, it was effective to use lactoperoxidase in large excess as compared with glucose oxidase, and to raise the concentration of bromide ion. However, the rate of glucose consumption was lowered at high concentrations of bromide ion, and at higher mole fraction of oxygen as compared with propylene in the gas mixture. Therefore, it seemed that for the favorable production of bromohydrin there existed the optimal conditions for the concentration of bromide ion and for the composition of oxygen-propylene gas mixture. Such kinetic behaviors of the sequential enzymatic reactions were explained by a mechanism involving free hypobromous acid as a reactive intermediate. Furthermore, the stability of the coimmobilized enzymes with k-carrageenan gels was investigated in continuous operations. The half-life of the enzymes was ca. 60 h for the production of propylene bromohydrin.
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PMID:Enzymatic formation of propylene bromohydrin from propylene by glucose oxidase and lactoperoxidase. 1855 22


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