Typically, such chromogenic substrates are composed of 3 to 5 natural or artificial amino acids. They may be N-terminally protected to reduce undesired degradation by aminopeptidases.
On their C-termini they are modified so that upon cleavage of the amide bond a chromogenic group is released. Most commonly used groups are the p-nitroaniline (pNA) which absorbs light of the wavelength of 405 nm.
Stability after reconstitution > 1 year (3 years from date of manufacture)
The substrates, after reconstitution with distilled water, are stable for 3 to 6 months between 2°C and 8°C.

Package Inserts, certificate of analysis supplied.
Material safety Data Sheet (MSDS) supplied.
Prolonged stability following reconstitution (> 3 months).
Discount according to quantities.