Assay of Angiotensin I by Fluorescence Polarization Method
Fluorescence polarization technique was applied for the assay of angiotensin I (Al) in human plasma. In this assay system, fluorescein labeled Al (F-Al), which retained the original antigenicity, and antibody to Al was allowed to interact in a cuvette in the instruments yielding an increase in the fluorescence polarization (P) value. Non-labeled Al in the sample blocked the binding of F-Al to the antibody resulting lower P value. Log of antigen concentration and P value was found to exhibit reverse linear proportionality between 0.05 ng to 2 ng/ml of antigen (Al) concentration. The present method was compared with standard radio-immunoassay method and the result showed that data were compatible with each other. The calculation of P value is automated and three cavity filter and optics of the instrument gave reliable results. The method is fast (<2 min), sensitive (<10 picomole/ml) and simple (no separation step before readout of the results).
KeywordsRenin Activity Phenyl Methyl Sulfonyl Fluoride Fluorescence Polarization Anode Voltage Phenyl Methyl Sulfonyl Fluoride
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