MeOSuc-AAPV-AMC (MeOSuc-Ala-Ala-Pro-Val-AMC) is a tetrapeptide that is a fluorescent substrate for human leukocyte and porcine pancreatic elastase.

1. Measurement of enzyme activity
Experimental steps:
1. Prepare the substrate solution: Dissolve MeOSuc-AAPV-AMC in an appropriate solvent (such as DMSO or water) and prepare the substrate solution at the desired concentration (usually 10–400 μM).
2. Reaction with elastase: Mix the substrate solution with elastase containing the appropriate concentration (human leukocyte elastase or porcine pancreatic elastase).
3. Incubate: Incubate the reaction mixture at 37°C for 30-60 minutes, allowing elastase to cleave the tetrapeptide substrate and release the AMC fluorophore.
4. Fluorescence measurement: Use a fluorescence spectrophotometer or microplate reader to measure the released fluorescence signal, the excitation wavelength is 360 nm and the emission wavelength is 460 nm. The fluorescence intensity is proportional to the activity of elastase.
2. Research on elastase inhibition
Experimental steps:
1. Prepare the substrate and enzyme mixture: Mix the MeOSuc-AAPV-AMC substrate with elastase and inhibitor.
2. Incubate: Incubate the mixture at appropriate temperature.
3. Fluorescence measurement: After incubation, measure the fluorescence signal and observe the inhibitory effect of the inhibitor on elastase activity.
III. Application in biological samples
Experimental steps:
1. Prepare samples: In some studies, biological samples (such as plasma, tissue extracts) need to be prepared to detect elastase activity.
2. Reaction with MeOSuc-AAPV-AMC: Mix the prepared samples with the substrate and incubate.
3. Fluorescence analysis: Through fluorescence analysis, the activity of elastase in the sample is evaluated.