Enzyme-protein/peptide conjugates, or cross-linked enzymes, are constructed for different applications. A typical example is the conjugation of “activated” horseradish peroxidase (HRP) to target antibody, protein, or peptide in immunoassays. On the other hand, cross-linking of enzyme molecules, as carrier-free immobilization technology, can expand industrial enzyme arsenal by increasing stability during use and storage. The conjugation reaction with proteins or peptides is usually via small molecular linkers (e.g. glutaraldehyde) or enzymes (e.g. transglutaminase), also known as cross-linking procedures.

In research and laboratory assays, modified enzyme horseradish peroxidase (HRP) is used extensively in immunoassay applications, where it spontaneously conjugates with amines on an antibody (or other protein) and produces a detectable signal in the presence of a substrate. This application can be regarded as a type of protein/peptide labeling.

In industry, though enzymatic reactions have advantages of high selectivity and efficiency, they have drawbacks such as lacking operational and storage stability. Therefore, cross-linked enzymes, typically produced by mixing an aqueous solution of the enzyme with an aqueous solution of glutaraldehyde, are applied to improve the enzymes with high productivities and avoids the costs of a carrier. This application is also known as a type of enzyme immobilization.

Creative Enzymes provides modified horseradish peroxidase (HRP), alkaline phosphatase (AP), and other instrumental enzymes for easy conjugation to proteins and peptides for various immunoassays and related applications. We also have extensive experience to develop CLEAs for improved properties of enzymes. We provide services to analyze the structures of enzyme complexes after conjugation and purification. Some highlighted services include:

• Immunoassays development.
• Preparation of cross-linked enzyme aggregates (CLEAs).
• Identification of structures of protein cross-linking.
• Enzyme conjugates characterization.

Related sections

Enzyme Engineering and Modification

Figure 1 A schematic illustration of CLEA preparation.
(Applied Microbiology and Biotechnology 2011)