Beta-galactosidase Alpha Complementation Kit – Catalog #: K2010002

Beta-galactosidase Alpha Complementation Kit provides a ready-to-use set of components for building research assays based on reconstitution of E. coli β-galactosidase activity. The kit includes donor and acceptor fragments in lyophilized form, dedicated stabilization buffers for each fragment, a chromogenic substrate, a substrate buffer, and detailed instructions (Catalog K2010002). Storage is specified at −20 °C with avoidance of repeated freeze–thaw. This concise, clearly itemized bill of materials enables laboratories to standardize alpha-complementation method setup while maintaining straightforward SOP documentation and inventory traceability.

In alpha complementation, two inactive β-galactosidase fragments associate to restore enzymatic activity, allowing researchers to couple enzyme readout to an interaction of interest. Because activity appears only after fragment association, background before complementation can be managed during optimization. The lyophilized donor and acceptor support precise aliquoting and flexible buffer selection, while the included stabilization buffers streamline handling and help maintain performance during bench work. The chromogenic substrate and substrate buffer provide a consistent path to qualitative color development once complementation occurs, and the kit’s documentation fields—application notes including cloned enzyme donor immunoassays and ELISA—fit common research use cases.

Practical setup typically involves small pilot titrations to determine fragment ratios and buffer dilutions appropriate for the intended matrix. Teams often document pH and ionic strength, incubation time and temperature, and lot identifiers to ensure reproducibility across operators and instruments. The explicit kit contents and storage guidance in this offering help establish those records efficiently. Within research-only boundaries, the component mix and clear labeling make this kit a dependable, documentation-friendly starting point for laboratories developing alpha-complementation–based assays and training exercises.

Why researchers choose this kit:

• Complete set: donor & acceptor fragments, dedicated stabilization buffers, chromogenic substrate & buffer, and instructions
• Lyophilized enzyme fragments support precise aliquoting and flexible reconstitution
• Specified storage at −20 °C; purity noted as >95% for included enzymes
• Application notes include cloned enzyme donor immunoassays and ELISA
• Recombinant enzyme source and clearly listed keywords aid SOP/LIMS mapping

This product is for Research Use Only (RUO). It is not intended for diagnostic or therapeutic use.

About Beta-galactosidase Alpha Complementation

Beta-galactosidase Alpha-Complementation is a biochemical phenomenon first documented by Agnes Ullmann, while working in the lab of François Jacob and Jacques Monod. By means of molecular cloning, the native E. coli β-galactosidase enzyme can be split in two inactive fragments of different sizes. The smaller fragment, known as the alpha-peptide or enzyme donor, is about 100 amino residues in length and is inactive on its own (incapable of hydrolyzing a β-galactosidase substrate).

The larger fragment, known as the omega fragment or enzyme acceptor, is about 900 amino residues in length and is also inactive on its own. Upon mixing the enzyme donor with the enzyme acceptor, the β-galactosidase enzyme is reconstituted and is now capable of hydrolyzing colorimetric substrates such as ONPG.

Both enzyme donor and enzyme acceptor can be cloned and expressed in special E. coli strains to yield highly pure, zero-background enzyme fragments (i.e. an enzyme donor and enzyme acceptor without measurable catalytic activities, when assayed individually). Interestingly, it was discovered that various analytes can be conjugated to the enzyme donor moiety and the enzyme donor-enzyme acceptor association modulated by an analyte-binding molecule (such as an antibody).

As a result, an alpha-complementation-based assay can be developed.

References

• Kras, E. (2019). Beta-galactosidase: properties, structure and functions. New York: Nova Science Publishers.
• Arndt, T. (2017). Cloned Enzyme Donor Immunoassay. Lexikon Der Medizinischen Laboratoriumsdiagnostik, 1–2.
• Jeon, S. I., Yang, X., and Andrade, J. D. (2004). Modeling of homogeneous cloned enzyme donor immunoassay. Analytical Biochemistry, 333(1), 136–147.
• Tachi, T., Kaji, N., Tokeshi, M., and Baba, Y. (2009). Microchip-based Homogeneous Immunoassay Using a Cloned Enzyme Donor. Analytical Sciences, 25(2), 149–151.
• Khanna, P. L., and Worthy, T. E. (1993). CEDIA: A Recombinant-Based Homogeneous Enzyme Immunoassay.

Brochure

• Download Alpha Complementation Product Line Brochure.