A new, highly sensitive and specific assay for chymotrypsin.

Area of Science:

• Biochemistry
• Enzymology
• Analytical Chemistry

Background:

• Chymotrypsin is a key digestive enzyme.
• Accurate quantification of chymotrypsin is crucial for diagnosing various gastrointestinal and pancreatic conditions.
• Existing methods for chymotrypsin determination may lack sensitivity, specificity, or are complicated.

Purpose of the Study:

• To develop a simple, highly sensitive, and specific fluorometric assay for determining chymotrypsin activity.
• To introduce and characterize a novel substrate, N-glutaryl-glycyl-glycyl-l-phenylalanine beta-naphthylamide (GGPNA), for chymotrypsin detection.

Main Methods:

• A novel substrate, GGPNA, was synthesized and tested for its specificity and sensitivity towards chymotrypsin.
• Fluorometric measurements were employed to quantify chymotrypsin activity using GGPNA.
• The assay's performance was evaluated in the presence of other proteases, alpha2-Macroglobulin-bound chymotrypsin, and common biological interferents.

Main Results:

• GGPNA is highly specific for chymotrypsin, showing minimal degradation by other proteases like trypsin, elastase, and plasmin.
• The assay demonstrates exceptional sensitivity, detecting chymotrypsin concentrations as low as 1 ng/ml with linearity up to 3000 ng/ml.
• alpha2-Macroglobulin-bound chymotrypsin was hydrolyzed at approximately 2/3 the rate of free enzyme, indicating assay applicability to enzyme complexes.
• Bile pigments and blood traces did not interfere with the assay, confirming its robustness in biological samples.

Conclusions:

• The developed fluorometric assay using GGPNA is a simple, sensitive, and specific tool for chymotrypsin determination.
• GGPNA is a versatile substrate suitable for fluorometric, colorimetric, and histological analyses of chymotrypsin.
• This assay has potential applications in clinical diagnostics and biochemical research for accurate chymotrypsin quantification.