Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:6.3.4.6 (urease)
 7,490 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fetal calf serum asialofetuin was assayed in the sandwich format using biotinylated and fluoresceinated ricin toxin (B-RCA and F-RCA). The sandwiched species was captured on a biotin-BSA coated nitrocellulose membrane with streptavidin. Anti-fluorescein antibody-urease conjugate was bound to the complex, and detected and quantitated under microvolume conditions using the light addressable potentiometric sensor. As little as 250 pg of asialofetuin was detectable whereas fetuin gave no response at conditions as high as 32 ng. Using a competitive inhibition assay, we established that the binding constant for the asialofetuin-ricin complex was 3.6 x 10(8) M-1. This is in good agreement with data published using glycopeptides derived from asialofetuin, and RCA and the ricin agglutinin, RCA-120.
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PMID:Picogram detection levels of asialofetuin via the carbohydrate moieties using the light addressable potentiometric sensor. 859 57

Highly specific detection of human alpha 1-acid glycoprotein (AGP) and asialo-alpha 1-acid glycoprotein (asialo-AGP) was made possible by use of a sandwich immunoassay. The glycoproteins were sandwiched between biotinylated and fluoresceinated polyclonal rabbit anti-human AGP antibodies. Additionally, asialo-AGP could be distinctly detected, apart from AGP, via the formation of a heterosandwich immunoassay using biotinylated polyclonal rabbit anti-human AGP and the lectin, fluoresceinated ricin toxin. Streptavidin was added to the formed immunocomplexes and the immunocomplexes captured on a biotinylated nitrocellulose membrane. The signal generator, urease conjugate of an anti-fluorescein antibody, was then bound to the complex on the membrane. The rate of pH change under microvolume conditions (0.6 microliters) was monitored using a silicon chip-based, light addressable potentiometer sensor. Results indicated that AGP and asialo-AGP can be detected to the 2 pg level when two antibodies are used to form the immunocomplex. Asialo-AGP can be detected down to 250 pg when the heterosandwich immunoassay is used; this assay exhibited no response up to 10 ng for native AGP or asialofetuin. Both immunoassays can be used to quantify the level of AGP and asialo-AGP in solution. Although the assay presented is very specific for AGP, asialo-AGP and terminal galactose, it is readily adaptable for the detection of any glycoprotein and terminal carbohydrate (or branched structure) by use of a protein-specific antibody and various lectins.
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PMID:Detection of human asialo-alpha(1)-acid glycoprotein using a heterosandwich immunoassay in conjunction with the light addressable potentiometric sensor. 887 21