A simple method for selection of trypsin chromogenic substrates using combinatorial chemistry approach

Area of Science:

• Biochemistry
• Enzymology
• Peptide Chemistry

Background:

• Bovine beta-trypsin is a key enzyme in various biological processes.
• Developing specific and efficient chromogenic substrates is crucial for studying protease activity.
• Existing substrates like Bz-D,L-Arg-pNA (BAPNA) serve as benchmarks but can be improved.

Purpose of the Study:

• To synthesize a tetrapeptide combinatorial library as chromogenic substrates for bovine beta-trypsin.
• To identify highly active and specific substrates for trypsin using a novel library approach.
• To establish a straightforward method for designing protease chromogenic substrates.

Main Methods:

• Solid-phase peptide synthesis was employed to create the tetrapeptide library.
• The library incorporated a 5-amino-2-nitrobenzoic acid (Anb(5,2)) analog at the C-termini.
• Iterative deconvolution in solution was used to identify efficient substrates.

Main Results:

• Four efficient trypsin substrates were successfully identified from the combinatorial library.
• The most active substrate, Phe-Val-Pro-Arg-Anb(5,2)-NH(2), demonstrated 125-fold higher activity than BAPNA.
• The synthesized p-nitroanilide derivatives show promise for protease specificity investigations.

Conclusions:

• A straightforward and effective method for designing trypsin chromogenic substrate libraries was established.
• The novel substrates offer significantly enhanced activity and potential for studying protease specificity.
• This approach can be extended for the investigation of various protease activities.