A solid-phase assay for beta-1,4-galactosyltransferase activity in human serum using recombinant aequorin

Area of Science:

• Biochemistry
• Enzymology
• Assay Development

Background:

• Serum enzyme activity analysis is crucial for diagnostics.
• Existing assays for beta-1,4-galactosyltransferase (beta 1,4-GT) have limitations.
• A sensitive and rapid assay is needed for beta 1,4-GT detection.

Purpose of the Study:

• To develop a sensitive and rapid solid-phase assay for serum beta-1,4-galactosyltransferase (beta 1,4-GT) activity.
• To utilize the bioluminescent protein aequorin for enhanced product detection.
• To demonstrate the utility of aequorin in solid-phase assays.

Main Methods:

• Developed a solid-phase assay using immobilized neoglycoprotein (GlcNAc-BSA) as substrate.
• Employed recombinant aequorin as a bioluminescent label for product quantification.
• Quantified product using biotinylated Ricinus communis agglutinin-I and streptavidin-aequorin complex.

Main Results:

• The assay is sensitive, detecting down to 10(-19) mol of product.
• Beta 1,4-GT activity showed linear correlation with time and serum concentration.
• The assay is reproducible, has low background, and is completed within hours.
• Aequorin-based assays offer a wider linearity range compared to horseradish peroxidase.

Conclusions:

• The developed assay is effective for determining beta 1,4-GT activity in human serum and purified enzyme.
• Aequorin is a valuable tool for developing sensitive solid-phase assay methods.
• This assay provides a rapid, reproducible, and sensitive method for beta 1,4-GT analysis.