V. Raphel et al., THE N-ACYLPEPTIDE HYDROLASE FROM PORCINE INTESTINE - ISOLATION, SUBCELLULAR-LOCALIZATION AND COMPARATIVE HYDROLYSIS OF PEPTIDE AND ISOPEPTIDE BONDS, Biochimie, 75(10), 1993, pp. 891-897
The N-acylpeptide hydrolase from porcine intestinal mucosa was 2000-fo
ld purified by a five-step procedure. The resulting protein (about 300
kDa) is composed of four apparently identical N-acylated polypeptide
chains. The enzyme activity was found to be equally distributed along
the crypt-villus axis in the intestine and was characterized as a cyto
solic protein. Besides the ability of porcine intestinal APH to cleave
the first peptide bond in N-protected peptides (K(m):0.8 mM), it is w
orth stressing that the enzyme was also found to efficiently catalyze
the hydrolysis of the isopeptide bond in N-epsilon-Ac-L-Met-L-Lys (K(m
):0.7-1.1 mM). It is suggested that N-acylpeptide hydrolase might not
only be involved in the catabolism of intracellular N-acylated protein
catabolism but also be responsible for the biological utilization of
N-acylated food proteins.