The amino acid sequence of the 49.4 kDa
peptidase was 98% similar to the metallopeptidase AprX from a Pseudomonas fluorescens strain. The
peptidase showed maximum activity at pH 8 and 40 C and withstood general ultra-high temperature
(UHT) processing (138 C for 18 s) in skim milk, with 88.0 ± 7.7% of the initial enzyme activity remaining
after heating.