PepX from Lactobacillus helveticus: Automated multi-step purification and determination of kinetic parameters with original tripeptide substrates

- An automated purification method in less than 6 h was developed.
- According to silver stained SDS-PAGE PepX was purified to homogeneity.
- The kinetics of PepX with different original tripeptides was studied for the first time.
- The amino acids at position P2 and P1′ showed a strong influence on the kinetic parameters.
- Original tripeptides possessed lower Km values than artificial chromogenic peptides.