When the two most important biological molecules, enzymes and nucleic acids, are combined, the convenience and versatility enables countless possibilities in biological research. For example, nucleic acid-enzyme conjugates were developed for DNA labeling aim at the booming field of biosensors. The technology has gained much interest since the detection of specific DNA sequences has applied in medical diagnostics, gene expression analysis, detection of infectious diseases and biological warfare agents. Horseradish peroxidase (HRP) is another example of the most commonly used enzymes in these applications. Direct conjugation of the ssDNA detection probe with HRP (ssDNA-HRP conjugate) has been used in both colorimetric and electrochemical assays as a sensitive detection probe in combination with streptavidin-HRP “indirectly”.

In general, “indirect” methods involve the detection of biotinylated or hapten-labeled probes by modified protein complexes. For example, complexes of alkaline phosphatase (AP), which catalyze dye precipitation, are used to detect biotinylated nucleic acids. For direct detection system, the enzyme is first modified with a synthetic polymer carrying many primary amino groups, followed by interaction with DNA with formation of covalent bonds. Recently, to amplify the signal during the detection step, a unique DNA sensing platform is developed based on an HRP-DNA binding protein tag conjugate and a hybrid ssDNA-dsDNA detection probe.

Creative Enzymes provides modified signal enzymes or DNA probes labeled with signal enzymes for detection of specific DNA sequences. With advanced techniques and instruments, we strictly monitor the procedures of protein expression, purification and the conjugation reaction, followed by the characterization of target conjugates. Feel free to contact us about our powerful tools in enzyme-nucleic acid conjugation:

• Development of enzyme linked oligonucleotide.
• Antibody-enzyme conjugates (AEC) preparation.
• Protein expression, purification and the conjugation reaction.
• Characterization of target conjugates.

Related sections

Enzyme Engineering and Modification

Figure 1 Genosensor signal amplification approaches using probe-HRP conjugates.
(Biosensors and Bioelectronics 2015)