Alpha-lytic protease

Alpha-lytic protease (aLP) is an alternative specificity protease for proteomics applications. This protease cleaves after T, A, S, and V residues. It generates peptides of similar average length as trypsin.

aLP was first isolated from the myxobacterium Lysobacter enzymogenes. The pro-form of aLP is 397 amino acids long. In its mature form, aLP is 198 amino acids long. Its tertiary structural core resembles those of pancreatic serine proteases.

Crystal structure studies of aLP have been reported. Several studies are available on the active site and catalytic mechanism of aLP. The role of the pro-region in the activation, secretion and folding of aLP has been studied.

The activity of aLP in the presence of various solution components is as follows:

• 0.1% sodium deoxycholate: ~1.75-fold enhanced activity
• 1.0% sodium deoxycholate: ~60% activity
• 0.1% SDS: ~50% activity
• 1.0% SDS: ~40% activity
• 1 M guanidine HCl: ~20% activity
• 4 M guanidine HCl: ~1% activity (essentially inactivated)

Supplied as a solution in 10 mM sodium acetate buffer, pH 5.0.

One unit will produce one mmole of p-nitroaniline per minute from N-succinyl-Ala-Ala-Ala-PNA at 25 °C at pH 7.5