Alkaline phosphatase SPDP activated

Reduction of the cystamine-labeled oligo using a disulfide reducing agent releases 2-mer-captoethylamine and creates a thiol group for conjugation (Figure 27.6). DNA probes labeled in this manner have been successfully coupled with SPDP-activated alkaline phosphatase (Chapter 26, Sections 1.2 and 2.5), maleimide-activated horseradish peroxidase (HRP) (Chapter 26, Section 1.1), NHS-LC-biotin (Chapter 11, Section 1 and Chapter 27, Section 2.3), and the fluorescent tag AMCA-HPDP (Chapter 9, Section 3 and Chapter 27, Section 2.5). 

Prepare SPDP-activated alkaline phosphatase in 50 mM sodium phosphate, 0.15M NaCl, lOmM EDTA, pH 7.2. Add to the oligo solution, an amount of the activated enzyme representing a 10-fold molar excess over the calculated amount of DNA present. 

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