Highly sensitive high-performance liquid chromatography-fluorimetric assay method for carboxypeptidase H activity

Area of Science:

• Biochemistry
• Analytical Chemistry
• Neuroscience

Background:

• Carboxypeptidase H is an enzyme crucial for neuropeptide processing.
• Accurate and sensitive assays are needed to study its activity in various tissues.
• Existing methods may lack the speed or sensitivity required for comprehensive analysis.

Purpose of the Study:

• To develop a rapid and sensitive high-performance liquid chromatographic (HPLC)-fluorimetric assay for carboxypeptidase H activity.
• To validate the method using specific substrates and buffers.
• To demonstrate the utility of the assay in detecting enzyme activity in biological samples.

Main Methods:

• Development of an HPLC-fluorimetric assay using N-(5-dimethyl-aminonaphthalene-1-sulfonyl)glycine (dansyl-Gly) as a marker.
• Enzymatic cleavage of dansyl-Gly-L-Lys or dansyl-Gly-L-Arg by carboxypeptidase H.
• Optimization of buffer conditions (pH 7.0 with 60% methanol) for rapid separation of product and substrate in under 5 minutes.

Main Results:

• Successful development of a rapid (under 5 min) and sensitive HPLC-fluorimetric assay.
• Demonstrated separation of the product (dansyl-Gly) from substrates using optimized buffer conditions.
• Detected carboxypeptidase H activity in rat sciatic nerve tissue samples.

Conclusions:

• The developed HPLC method provides a robust tool for quantifying carboxypeptidase H activity.
• This assay facilitates the study of enzyme activity across diverse tissue types.
• The method's speed and sensitivity enhance the investigation of carboxypeptidase H's physiological roles.