Homogeneous Enzyme-Linked Binding Assay Mediated by the Interaction of Avidin with Biotin: Mistletoe Lectin I Assay

Abstract

We have examined the feasibility of using the specific interaction between mistletoe lectin I (ML I) and <TEX>${\beta}$</TEX>-Dgalactose instead of the anti-ML I antibody in developing a homogeneous type competitive binding assay for ML I. We also have examined the feasibility of adapting the biotin/avidin mediated homogeneous assay for this system. Alkaline phosphatase (AKP) was employed as a single substrate enzyme label. The dose-response curve shows a detection range of 1-25 <TEX>${\mu}$</TEX>g/mL and a linear response with a correlation coefficient of 0.99. To demonstrate the analytical utility of this method, 10 <TEX>${\mu}$</TEX>g/mL of ML I was spiked into distilled water. The results show that the mean recovery was 10.03 <TEX>${\mu}$</TEX>g/mL with an SD of 0.18. The difference between the spiked value and the mean recovery was 0.03 <TEX>${\mu}$</TEX>g/mL, with a relative error of 0.3 and 1.6 % of RSD.